Carbon nanotube thermal emission source and generating broadband thermal radiation

Abstract

A carbon nanotube thermal emission source generates broadband thermal radiation and includes: an off-axis parabolic mirror in optical communication with a laser light source and a carbon nanotube thin film emitter; a vacuum chamber in which is disposed the carbon nanotube thin film emitter; an infrared-visible transmissive window disposed on the vacuum chamber; the carbon nanotube thin film emitter disposed in the vacuum chamber; vertically aligned carbon nanotubes disposed on a thermally insulating substrate; and the substrate on which is disposed the vertically aligned carbon nanotubes. The carbon nanotube thermal emission source can include a radiation analyzer in optical communication with the sample to analyze sample radiation and to produce spectral information about the sample from the analysis of sample radiation.

Description

CARBON NANOTUBE THERMAL EMISSION SOURCE AND GENERATINGBROADBAND THERMAL RADIATIONSTATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

[0001] This invention was made with United States Government support from the National Institute of Standards and Technology (NIST), an agency of the United States Department of Commerce. The Government has certain rights in this invention.CROSS REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application Serial Nos. 63 / 570,475 (filed 03 / 27 / 2024) and 63 / 599,590 (filed 11 / 16 / 2023), both of which are herein incorporated by reference in their entirety.BRIEF DESCRIPTION

[0003] Disclosed is a carbon nanotube thermal emission source for generating broadband thermal radiation, comprising: An off-axis parabolic mirror in optical communication with a laser light source and in optical communication with a carbon nanotube thin film emitter, comprising a primary surface, a parabolic surface, and a through aperture that is bounded by an aperture wall, such that the off-axis parabolic mirror receives laser light in the through aperture, communicates laser light through the through aperture to the carbon nanotube thin film emitter, receives thermal radiation from the carbon nanotube thin film emitter at the parabolic surface, and reflects thermal radiation from the parabolic surface; a vacuum chamber in which is disposed the carbon nanotube thin film emitter, in optical communication with the off-axis parabolic mirror and in mechanical communication with the carbon nanotube thin film emitter, and that houses the carbon nanotube thin film emitter, receives laser light that is communicated through the aperture wall of the off-axis parabolic mirror and an infrared-visible transmissive window, communicates thermal radiation produced from the carbon nanotube thin film emitter to the parabolic surface of the off-axis parabolic mirror via the infrared-visible transmissive window, such that an interior of the vacuum chamber in which the carbonnanotube thin film emitter is disposed provides a pressure less than 10-3Torr and a gas environment that has a lower number density of oxidants that include oxygen than ambient air to avoid oxidation of the carbon nanotube thin film emitter when the carbon nanotube thin film emitter is subjected to heating by receipt of laser light; an infrared- visible transmissive window disposed on the vacuum chamber, in mechanical communication with the vacuum chamber and in optical communication with the off-axis parabolic mirror and the carbon nanotube thin film emitter, and that receives laser light that is communicated through the aperture wall of the off-axis parabolic mirror, communicates laser light to the carbon nanotube thin film emitter, receives thermal radiation from the carbon nanotube thin film emitter, communicates thermal radiation to the parabolic surface of the off-axis parabolic mirror, such that the vacuum chamber in combination with the infrared-visible transmissive window provides the pressure less and the gas environment that avoids oxidation of the carbon nanotube thin film emitter when the carbon nanotube thin film emitter is subjected to heating by receipt of laser light; a carbon nanotube thin film emitter disposed in the vacuum chamber, in mechanical communication with the vacuum chamber and in optical communication with the off-axis parabolic mirror and the infrared-visible transmissive window, and that comprises vertically aligned carbon nanotubes and a substrate, such that the vertically aligned carbon nanotubes receive laser light from the vacuum chamber, optically absorb laser light, produce thermal radiation in response to the optical absorption of laser light, and radiate thermal radiation to the parabolic surface of the off-axis parabolic mirror via communication through the infrared-visible transmissive window; vertically aligned carbon nanotubes disposed on the substrate, disposed in the vacuum chamber, in mechanical communication with the substrate and the vacuum chamber and in optical communication with the off-axis parabolic mirror and the infrared-visible transmissive window, and that receive laser light from the vacuum chamber, optically absorb laser light, produce thermal radiation in response to the optical absorption of laser light, and radiate thermal radiation to the parabolic surface of the off-axis parabolic mirror via communication through the infrared-visible transmissive window; and the substrate on which the vertically aligned carbon nanotubes are disposed, disposed in the vacuum chamber, in mechanical communication with the vertically aligned carbon nanotubes and the vacuum chamber and that provides a thermally stable and chemically stable mechanical mount by which the carbon nanotube thin film emitter is mounted to the interior of the vacuum chamber, such that the vertically aligned carbon nanotubes are optically interposed between the off-axis parabolic mirror and the substrate, and the substrate is mechanically interposed between the vertically aligned carbon nanotubes and the vacuum chamber.

[0004] Disclosed is a process for generating broadband thermal radiation, comprising: providing a carbon nanotube thin film emitter; providing a vacuum chamber in which the carbon nanotube thin film emitter is disposed; providing an off-axis parabolic mirror in optical communication with the carbon nanotube thin film emitter; providing an infrared-visible transmissive window disposed on the vacuum chamber; communicating laser light to the carbon nanotube thin film emitter through the infrared-visible transmissive window; optically absorbing the laser light by the carbon nanotube thin film emitter; producing thermal radiation in response to the optical absorption of laser light; and radiating the thermal radiation to the parabolic surface of the off-axis parabolic mirror.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The following description cannot be considered limiting in any way. Various objectives, features, and advantages of the disclosed subject matter can be more fully appreciated with reference to the following detailed description of the disclosed subject matter when considered in connection with the following drawings, in which like reference numerals identify like elements.

[0006] FIG. 1 shows, according to some embodiments, a carbon nanotube thermal emission source 200.

[0007] FIG. 2 shows, according to some embodiments, a carbon nanotube thermal emission source 200.

[0008] FIG. 3 shows, according to some embodiments, a carbon nanotube thermal emission source 200.

[0009] FIG. 4 shows, according to some embodiments, a carbon nanotube thin film emitter 106.

[0010] FIG. 5 shows, according to some embodiments, a carbon nanotube thermal emission source 200.

[0011] FIG. 6 shows, according to some embodiments, a carbon nanotube thermal emission source 200.

[0012] FIG. 7 shows, according to some embodiments, a carbon nanotube thermal emission source 200, wherein a conical mirror is aligned proximate to a vacuum chamber.

[0013] FIG. 8 shows, according to some embodiments, a carbon nanotube thin film emitter 106 with laser light off and on, wherein lighter regions are warmer and darker are cooler.

[0014] FIG. 9 shows, according to some embodiments, a graph of spectral irradiance versus wavelength for a predicted blackbody spectral irradiance of a carbon nanotube thermal emission source 200 for 3000 K, 2000 K and 1000 K operating temperature.

[0015] FIG. 10 shows, according to some embodiments, a computing system for performing certain analysis of sample radiation 119 with radiation analyzer 118.

[0016] FIG. 11 shows, according to some embodiment,carbon nanotube thermal emission source 200.

[0017] FIG. 12 shows, according to some embodiment, a carbon nanotube thermal emission source 200.

[0018] FIG. 13 shows, according to some embodiment, a carbon nanotube thermal emission source 200.DETAILED DESCRIPTION

[0019] A detailed description of one or more embodiments is presented herein by way of exemplification and not limitation.

[0020] Conventional thermal emission sources, such as those using incandescent filaments, suffer from a number of deficiencies. These sources are inefficient, as much of the energy they consume is lost as heat. They are also bulky and fragile, and they have a limited lifespan. In addition, they emit light in a broad spectrum,which can be undesirable in some applications. Further, conventional thermal emitters often do not emit sufficient infrared photon flux for performing microscopy.

[0021] It has been discovered that a carbon nanotube thermal emission source 200 overcomes these deficiencies and generates broadband thermal radiation for infrared spectroscopy. The carbon nanotube thermal emission source 200 is highly efficient, as the carbon nanotubes convert a large fraction of the energy they receive into thermal radiation. The carbon nanotube thermal emission source 200 is also compact and robust, and carbon nanotube thermal emission source 200 has a long lifespan. In addition, the carbon nanotube thermal emission source 200 emits thermal radiation in a broad band of wavelengths, which can be tailored to specific applications. The carbon nanotube thermal emission source 200 is a significant improvement over conventional thermal emission sources. It is more efficient, compact, robust, and versatile

[0022] Carbon nanotube thermal emission source 200 generates broadband thermal radiation. In an embodiment, with reference to FIG. 1 , FIG. 2, FIG. 3, FIG. 4, FIG. 5, FIG. 6, FIG. 8, FIG. 9, and FIG. 10, carbon nanotube thermal emission source 200 for generating broadband thermal radiation includes: an off-axis parabolic mirror 103 in optical communication with a laser light source 112 and a carbon nanotube thin film emitter 106, including a primary surface 115, a parabolic surface 116, and a through aperture 113 that is bounded by an aperture wall 114, such that the off-axis parabolic mirror 103 receives laser light 100 in through aperture 113, communicates laser light 100 through the through aperture 113 to the carbon nanotube thin film emitter 106, receives thermal radiation 109 from the carbon nanotube thin film emitter 106 at the parabolic surface 116, and reflects thermal radiation 109 from the parabolic surface 116; a vacuum chamber 104 in which the carbon nanotube thin film emitter 106 is disposed and in optical communication with the off-axis parabolic mirror 103 and in mechanical communication with the carbon nanotube thin film emitter 106, receiving laser light 100 that is communicated through the aperture wall 114 of the off-axis parabolic mirror 103 and an infrared-visible transmissive window 105, communicating thermal radiation 109 produced from the carbon nanotube thin film emitter 106 to the parabolic surface 116 of the off-axis parabolic mirror 103 via the infrared-visible transmissive window 105, such that an interior of the vacuum chamber 104 in which the carbon nanotube thin film emitter 106 is disposed provides a pressure less than 10-3Torr and a gas environment that has a lower number density of oxidants that contain oxygen than ambient air to avoid oxidation of the carbonnanotube thin film emitter 106 when the carbon nanotube thin film emitter 106 is subjected to heating by receipt of laser light 100; an infrared-visible transmissive window 105 disposed on the vacuum chamber 104 and in mechanical communication with the vacuum chamber 104 and in optical communication with the off-axis parabolic mirror 103 and the carbon nanotube thin film emitter 106, receiving laser light 100 that is communicated through the aperture wall 114 of the off-axis parabolic mirror 103, communicating laser light 100 to the carbon nanotube thin film emitter 106, receiving thermal radiation 109 from the carbon nanotube thin film emitter 106, communicating thermal radiation 109 to the parabolic surface 116 of the off-axis parabolic mirror 103, such that the vacuum chamber 104 in combination with the infrared-visible transmissive window 105 provides the pressure less and the gas environment that avoids oxidation of the carbon nanotube thin film emitter 106 when the carbon nanotube thin film emitter 106 is subjected to heating by receipt of laser light 100; a carbon nanotube thin film emitter 106 disposed in the vacuum chamber 104 and in mechanical communication with the vacuum chamber 104 and in optical communication with the off-axis parabolic mirror 103 and the infrared-visible transmissive window 105, including vertically aligned carbon nanotubes 110 and a substrate 111 , such that the vertically aligned carbon nanotubes 110 receive laser light 100 from the vacuum chamber 104, optically absorb laser light 100, produce thermal radiation 109 in response to the optical absorption of laser light 100, and radiate thermal radiation 109 to the parabolic surface 116 of the off-axis parabolic mirror 103 via communication through the infrared-visible transmissive window 105; the vertically aligned carbon nanotubes 110 disposed on the substrate 111 and disposed in the vacuum chamber 104 and in mechanical communication with the substrate 111 and the vacuum chamber 104 and in optical communication with the off-axis parabolic mirror 103 and the infrared-visible transmissive window 105 and that receives the laser light 100 from the off- axis parabolic mirror 103, optically absorbs the laser light 100, produces the thermal radiation 109 in response to the optical absorption of the laser light 100, radiates the thermal radiation 109 to the parabolic surface 116 of the off-axis parabolic mirror 103 via communication through the infrared-visible transmissive window 105; and the substrate 111 on which is disposed the vertically aligned carbon nanotubes 110 and that is disposed in the vacuum chamber 104 and in mechanical communication with the vertically aligned carbon nanotubes 110 and the vacuum chamber 104 and that provides a thermally stable and chemically stable mechanical mount by which the carbon nanotube thin film emitter 106 is mounted to the interior of the vacuum chamber 104, such that the vertically alignedcarbon nanotubes 110 are optically interposed between the off-axis parabolic mirror 103 and the substrate 111 , and the substrate 111 is mechanically interposed between the vertically aligned carbon nanotubes 110 and the vacuum chamber 104.

[0023] In an embodiment, carbon nanotube thermal emission source 200 includes a laser light source 112 in optical communication with off-axis parabolic mirror 103 and carbon nanotube thin film emitter 106 and that produces laser light 100, communicates laser light 100 to carbon nanotube thin film emitter 106 through optical communication through off-axis parabolic mirror 103. The laser light source 112 produces laser light 100, which is communicated to the carbon nanotube thin film emitter 106 through optical communication through off-axis parabolic mirror 103. The carbon nanotube thin film emitter 106 is in optical communication with the off-axis parabolic mirror 103 and in optical communication with the laser light source 112. The off-axis parabolic mirror 103 is in optical communication with the laser light source 112 and in optical communication with the carbon nanotube thin film emitter 106.

[0024] In an embodiment, carbon nanotube thermal emission source 200 includes plane mirror 101 , in optical communication with laser light source 112 and off- axis parabolic mirror 103 and receives laser light 100 from laser light source 112, and reflects laser light 100 to off-axis parabolic mirror 103, such that plane mirror 101 is optically interposed between laser light source 112 and off-axis parabolic mirror 103.

[0025] In an embodiment, carbon nanotube thermal emission source 200 includes lens 102, which is in optical communication with laser light source 112, off-axis parabolic mirror 103, and carbon nanotube thin film emitter 106, and which receives laser light 100 from laser light source 112, focuses laser light source 112 into off-axis parabolic mirror 103 and onto carbon nanotube thin film emitter 106, such that lens 102 is optically interposed between laser light source 112 and off-axis parabolic mirror 103.

[0026] In an embodiment, carbon nanotube thermal emission source 200 includes: a through aperture 113 disposed in off-axis parabolic mirror 103 and in optical communication with laser light source 112 and carbon nanotube thin film emitter 106 and that is bounded by aperture wall 114, extends through off-axis parabolic mirror 103 from primary surface 115 to parabolic surface 116, and receives laser light 100, and communicates laser light 100 through off-axis parabolic mirror 103 to carbon nanotube thin film emitter 106; aperture wall 114 disposed in off-axis parabolic mirror 103 and inoptical communication with laser light source 1 12 and in optical communication with carbon nanotube thin film emitter 106 and that bounds aperture wall 114, and receives laser light 100, and communicates laser light 100 through off-axis parabolic mirror 103 to carbon nanotube thin film emitter 106; primary surface 115 disposed on off-axis parabolic mirror 103 and that is arranged at an acute angle to parabolic surface 116 that receives and reflects thermal radiation 109 from carbon nanotube thin film emitter 106; and parabolic surface 116 disposed on off-axis parabolic mirror 103 and in optical communication with carbon nanotube thin film emitter 106 and that comprises a parabolic shape and is arranged at an acute angle to primary surface 115, and receives thermal radiation 109 from carbon nanotube thin film emitter 106 and reflects thermal radiation 109, such that rays of thermal radiation 109 reflected from parabolic surface 116 are parallel to one another.

[0027] In an embodiment, carbon nanotube thermal emission source 200 includes mounting post 107 is disposed on the substrate 111 and is disposed in the vacuum chamber 104. The mounting post 107 is in mechanical communication with the substrate 111 and is in mechanical communication with the vacuum chamber 104. The mounting post 107 provides a thermally stable and mechanical mount by which the carbon nanotube thin film emitter 106 is mounted to the interior of the vacuum chamber 104. The mounting post 107 is mechanically interposed between the substrate 111 and the vacuum chamber 104.

[0028] In an embodiment, carbon nanotube thermal emission source 200 includes vacuum pump 108 that is disposed on vacuum chamber 104 and in mechanical communication with vacuum chamber 104 and in fluid communication with carbon nanotube thin film emitter 106. The vacuum pump 108 evacuates vacuum chamber 104 and removes gases in vacuum chamber 104 to obtain the pressure that is less than 10-3Torr and gas environment that has a lower number density of oxidants that include oxygen than ambient air to avoid oxidation of carbon nanotube thin film emitter 106 when carbon nanotube thin film emitter 106 is subjected to heating by receipt of laser light 100.

[0029] In an embodiment, carbon nanotube thermal emission source 200 includes sample 117 that is in optical communication with the off-axis parabolic mirror 103 and the carbon nanotube thin film emitter 106. The sample 117 includes an infrared absorbable analyte. The sample 117 receives thermal radiation 109 reflected from theparabolic surface 116 of the off-axis parabolic mirror 103. The sample 117 produces sample radiation 119 from absorption of the thermal radiation 109.

[0030] In an embodiment, carbon nanotube thermal emission source 200 includes radiation analyzer 118 in optical communication with sample 117 and that receives sample radiation 119 from sample 117, analyzes sample radiation 119, and produces spectral information about sample 117 from the analysis of sample radiation 119.

[0031] In an embodiment, carbon nanotube thermal emission source 200 produces high brightness broadband infrared radiation by focusing a laser onto the surface of carbon nanotube thin film emitter 106. The focused light locally heats the carbon nanotubes through optical absorption. Since carbon nanotubes have a near unity absorption, they efficiently absorb the incident radiation. The locally heated spot then begins emitting a blackbody spectrum with a near unity emissivity. Carbon nanotubes are thermally stable at high temperatures in excess of 3000 K. Emitted light as thermal radiation 109 is collimated by a section of conic mirror 103 for a spectroscopic application. At elevated temperatures, carbon nanotubes interact with components in the ambient atmosphere which changes its absorption and thermal properties. To avoid this, carbon nanotube thin film emitter 106 is disposed in a vacuum chamber and held at rough vacuum when in operation.

[0032] Carbon nanotube thermal emission source 200 can be made of various elements and components that can be assembled together or fabricated. Elements of carbon nanotube thermal emission source 200 can be various sizes and shapes. Elements of carbon nanotube thermal emission source 200 can be made of a material that is physically or chemically resilient in an environment in which carbon nanotube thermal emission source 200 is disposed. Exemplary materials include a metal, ceramic, thermoplastic, glass, semiconductor, and the like. The elements of carbon nanotube thermal emission source 200 can be made of the same or different material and can be monolithic in a single physical body or can be separate members that are physically joined.

[0033] The carbon nanotube thermal emission source 200 is a device that generates broadband thermal radiation and can include an off-axis parabolic mirror 103, a vacuum chamber 104, an infrared-visible transmissive window 105, a carbon nanotubethin film emitter 106, vertically aligned carbon nanotubes 110, a substrate 111 , and a radiation analyzer 118. The off-axis parabolic mirror 103 receives laser light 100 from a laser light source 112 and communicates laser light 100 through the through aperture 113 to the carbon nanotube thin film emitter 106. The vacuum chamber 104 houses the carbon nanotube thin film emitter 106 and provides a pressure less than 10-3Torr and gas environment that has a lower number density of oxidants that include oxygen than ambient air to avoid oxidation of the carbon nanotube thin film emitter 106 when the carbon nanotube thin film emitter 106 is subjected to heating by receipt of laser light 100. The infrared-visible transmissive window 105 receives laser light 100 that is communicated through aperture wall 114 of the off-axis parabolic mirror 103 and communicates thermal radiation 109 produced from the carbon nanotube thin film emitter 106 to the parabolic surface 116 of the off-axis parabolic mirror 103 via communication through the infrared-visible transmissive window 105. The carbon nanotube thin film emitter 106 includes vertically aligned carbon nanotubes 110 and a substrate 111. The vertically aligned carbon nanotubes 110 receive laser light 100 from the vacuum chamber 104, optically absorb laser light 100, produce thermal radiation 109 in response to the optical absorption of laser light 100, and radiate thermal radiation 109 to the parabolic surface 116 of the off-axis parabolic mirror 103 via communication through the infrared- visible transmissive window 105. The substrate 111 provides a thermally stable and chemically stable mechanical mount by which the carbon nanotube thin film emitter 106 is mounted to the interior of the vacuum chamber 104. The radiation analyzer 118 is in optical communication with the sample 117 and receives sample radiation 119 from the sample 117. The radiation analyzer 118 analyzes the sample radiation 119 and produces spectral information about the sample 117 from the analysis of the sample radiation 119.

[0034] The laser light 100 is a collimated beam of light that is produced by a laser light source. Lasers are devices that produce light by stimulated emission of radiation. This means that the light is produced by atoms or molecules that are excited to a higher energy state and then emit light when they return to a lower energy state. The light produced by a laser is very intense and has a very narrow wavelength. This makes it ideal for use in a variety of applications, including spectroscopy, medicine, and manufacturing.

[0035] The laser light 100 in the carbon nanotube thermal emission source 200 is used to excite the carbon nanotubes in the thin film emitter 106. When the carbonnanotubes are excited, they emit thermal radiation. This thermal radiation is then reflected by the off-axis parabolic mirror 103 and focused onto the sample 117. The radiation analyzer 118 then analyzes the sample radiation 119 and produces spectral information about the sample 117. The laser light 100 has a number of properties that make it useful in the carbon nanotube thermal emission source 200. These properties can include: a selected intensity, wherein laser light 100 can be very intense, which means that it can excite a large number of carbon nanotubes at the same time. This results in a high level of thermal radiation being emitted from the thin film emitter 106. Laser light 100 can have a selected wavelength, e.g., a narrow wavelength that can be monochromatic so that thermal radiation emitted from the thin film emitter 106 is also monochromatic. This makes it easier to analyze the sample radiation 119. Laser light 100 can be a collimated beam such that rays in laser light are parallel and thermal radiation emitted from the thin film emitter 106 can be collimated and focused onto sample 117.

[0036] The laser light source 112 is a device that emits laser light 100. Laser light is a type of light that is produced by a process called stimulated emission. Stimulated emission is a process in which an atom or molecule is excited to a higher energy state by absorbing a photon of light. When the atom or molecule decays back to its ground state, it emits a photon of light with the same energy as the photon that it absorbed. This process can be repeated many times, resulting in a beam of laser light. The laser light source 112 can be used for a variety of applications, including spectroscopy, microscopy, and surgery. The laser light source 112 has a number of properties that make it useful such as: producing a beam of laser light 100 with a high intensity. Various types of laser light source 112 can be used such as laser, flash lamp, synchrotron, and the like. In an embodiment, laser light source 112 is a laser with low beam divergence (<10 mrad half angle) and minimum optical power of >25 mW. Laser can be free space or fiber coupled

[0037] The plane mirror 101 can be a flat, smooth surface that reflects light in a selected direction. It can be made of a material that has a high refractive index, such as glass or metal. The mirror is used to reflect laser light 100 from the laser light source 112 to the carbon nanotube thin film emitter 106. The plane mirror 101 can have properties that make it useful in the carbon nanotube thermal emission source 200. Plane mirror 101 can be very reflective at the wavelength of laser light 100 so that it reflects a large percentage of the light that hits it and so that laser light source 112 provides enough light to the carbon nanotube thin film emitter 106. The plane mirror 101 can be flat so that thelight that is reflected from it is evenly distributed and ensures that the carbon nanotube thin film emitter 106 is heated evenly or at a particular spatial distribution. The plane mirror 101 can be durable to withstand high temperatures or pressures. In an embodiment, plane mirror 101 is disposed on a kinematic mount and aligned. The kinematic mount can provide at least 2 degrees of freedom of alignment for the plane mirror.

[0038] Carbon nanotube thermal emission source 200 can include lens 102. In an embodiment, lens 102 is interposed between laser light source 112 and carbon nanotube thin film emitter 106 as shown in FIG. 2. In an embodiment, lens 102 is interposed between carbon nanotube thin film emitter 106 and sample 117 as shown in FIG. 12. In an embodiment, carbon nanotube thermal emission source 200 includes a plurality of lenses 102 that can be interposed between laser light source 112 and carbon nanotube thin film emitter 106, between carbon nanotube thin film emitter 106 a sample 117, or a combination thereof. Lens 102 can be any curved surface that can collect light from a point source such as a refractive lens or curved mirror (off-axis paraboloid, elliptical, objective lens, and the like). Lens 102 can be, e.g., a plano-convex lens with a select focal length, e.g., of 100 mm. Lens 102 can be made of a material with a high refractive index, such as fused silica or sapphire. The lens can have a selected diameter, e.g., 25 mm, or a selected thickness, e.g., 10 mm. The lens can be mounted in a holder that is attached to the vacuum chamber 104. The lens focuses the laser light 100 to the carbon nanotube thin film emitter 106 through the through aperture 113 of off-axis parabolic mirror 103. The lens 102 can have a high refractive index that can focus the laser light 100 onto a select spot size on carbon nanotube thin film emitter 106. The lens 102 can have a low absorption coefficient so that it does not absorb much of the laser light 100 and a maximum amount of laser light 100 is available for optical absorption by carbon nanotube thin film emitter 106. The lens 102 can be very stable. The lens 102 can be made of a material that is resistant to thermal shock and vibration so that the lens 102 is not damaged by harsh environmental conditions. In an embodiment, lens 102 is a converging lens that is compatible with the wavelength of laser light 100. The focal length of lens 102 can have a focal length longer than that of off-axis parabolic mirror 103 plus the diameter of off-axis parabolic mirror 103 so that the lens can be sufficiently close to carbon nanotube thin film emitter 106 to produce an adequate focus. The blur size produced from the lens 102 can have a diameter less than 500 μm.

[0039] The off-axis parabolic mirror 103 is a partially reflective optical element that is used to communicate light from laser light source 112 onto carbon nanotube thin film emitter 106 and reflect 109 from 106 onto sample 117. The off-axis parabolic mirror 103 can be made of a material that has a high reflectivity for the wavelength of thermal radiation 109. The off-axis parabolic mirror 103 can be shaped to focus laser light 100 onto a selected spot size on carbon nanotube thin film emitter 106. This allows carbon nanotube thin film emitter 106 to be heated to a high temperature and to emit broadband thermal radiation 109. The off-axis parabolic mirror 103 can be efficient at reflecting thermal radiation 109 and can be stable such that it does not change shape or position over time, which maintains a consistent output from carbon nanotube thin film emitter 106 to sample 117. It is contemplated that off-axis parabolic mirror 103 includes a metallic section of a conic mirror with through aperture 113 (e.g., a tapered hole drilled through the center). The laser light is focused by element 102 and passes through the tapered hole. In an embodiment, off-axis parabolic mirror 103 is a section of a conic metallic mirror with a tapered through hole. The off-axis parabolic mirror 103 can be either an off-axis paraboloid or spherical mirror. The entrance of the through hole should have a diameter larger than the beam diameter from laser light 100.

[0040] In an embodiment, a spherical mirror with a solid angle of collection of 2 pi is used as off-axis parabolic mirror 103. A small, tapered hold is drilled at the base of the mirror. The carbon nanotube thin film emitter 106 is mounted at the focal lengths of the spherical mirror. This mirror is enclosed in a vacuum chamber with two optical access ports and a vacuum evacuation port. The laser light 100 is coupled through the tapered hole, and emission is collimated and sent in the same direction as the laser light 100.

[0041] The through aperture 113 is a small opening in the off-axis parabolic mirror 103 that allows laser light 100 to pass through to the carbon nanotube thin film emitter 106. The through aperture 113 is typically made of a material that is transparent to laser light, such as air, quartz, sapphire, and the like. The size and shape of the through aperture 113 can be factors in determining performance of the carbon nanotube thermal emission source 200. The through aperture 113 can be large enough to allow enough laser light 100 to pass through to the carbon nanotube thin film emitter 106. The through aperture 113 can be used to block a certain amount of so that it does not allow too much laser light 100 to pass through to avoid damage of the carbon nanotube thin film emitter 106. The through aperture 113 can be of a shape that focuses the laser light onto thecarbon nanotube thin film emitter 106 in a selected spatial shape or selected spatial distribution, e.g., a uniform spatial distribution. The through aperture 113 can be made in a variety of ways, including by drilling, laser cutting, or chemical etching. The through aperture 113 can also be made in a variety of sizes and shapes. The size and shape of the through aperture 113 will depend on the specific application of the carbon nanotube thermal emission source 200.

[0042] The aperture wall 114 is an interfacial surface of off-axis parabolic mirror 103 to through aperture 113 of the off-axis parabolic mirror 103. The aperture wall 114 can have a circular opening that is sized to allow laser light 100 to pass through the through aperture 113 and to the carbon nanotube thin film emitter 106. The aperture wall 114 can be made of a material that is transparent to laser light, such as quartz or sapphire. The aperture wall 114 has a thickness that is less than the wavelength of laser light, such that the aperture wall 114 does not diffract the laser light. The aperture wall 114 is also smooth, such that it does not scatter the laser light. The aperture wall 114 can be the exposed surface of off-axis parabolic mirror 103 proximate to aperture wall 114 or can be a thin film or insert of material, which allows laser light to pass through the through aperture 113 with minimal loss. The aperture wall 114 can be made of a material that is transparent to laser light, which allows the laser light to reach the carbon nanotube thin film emitter 106. The aperture wall 114 can be durable and withstand the high temperatures generated in the carbon nanotube thermal emission source 200.

[0043] The primary surface 115 is a reflective surface that is disposed on the off-axis parabolic mirror 103 opposing laser light source 112. The primary surface 115 can be made of a material that has a high reflectivity in the infrared and visible wavelengths, such as gold or silver. The primary surface 115 is also preferably smooth and flat, so that it can reflect laser light 100 with minimal scattering.

[0044] The parabolic surface 116 is a curved surface that reflects thermal radiation 109 in a parallel beam. The shape of the surface is such that rays of thermal radiation 109 that strike the parabolic surface 116 at the same angle are reflected back at the same angle. Accordingly, parabolic surface 116 provides the thermal radiation 109 from the carbon nanotubes to be focused in a single direction. The parabolic surface 116 can be made of a material that is both reflective and durable, such as metal or glass. The surface can be coated with a thin layer of a material that reflects infrared light. This coating helps to improve the efficiency of the carbon nanotube thermal emission sourceby reflecting more of the thermal radiation towards the sample 117. The parabolic surface 116 can be mounted on a support structure that allows it to be positioned in front of the carbon nanotube thin film emitter 106. The support structure can be adjustable to allow for fine-tuning of the focus of the parabolic surface 116.

[0045] The vacuum chamber 104 is a sealed enclosure that is maintained at a pressure below atmospheric pressure. The vacuum chamber 104 can be made of metal or optical material, e.g., glass, and it can be, e.g., cylindrical, or rectangular in shape. The vacuum chamber 104 can have a variety of ports (e.g., two, three, ..., n, wherein n is an integer selected for a particular application) and openings for the introduction of materials, the removal of certain materials, and monitoring of conditions within the chamber. The vacuum chamber 104 is used to create a low-pressure environment for a variety of purposes. In the case of the carbon nanotube thermal emission source 200, the vacuum chamber 104 is used to prevent the oxidation of the carbon nanotubes. The low-pressure environment also helps to improve the efficiency of the carbon nanotubes as a thermal emission source. The vacuum chamber 104 is evacuated using a vacuum pump 108. The vacuum pump 108 removes fluid, e.g., air and other gases, from the vacuum chamber104, creating a low-pressure environment. The vacuum chamber 104 can be equipped with a pressure gauge to monitor the pressure within the chamber.

[0046] The infrared-visible transmissive window 105 can be a material that is transparent to visible light and infrared light. It can be made of a material such as silicon dioxide or sapphire, and it is used to allow laser light 100 to pass through from the laser light source 112 to the carbon nanotube thin film emitter 106. The infrared-visible transmissive window 105 has a high transmission coefficient for visible light and infrared light, and it can be resistant to oxidation and other environmental damage. The infrared- visible transmissive window 105 is mounted on the vacuum chamber 104 using adhesive or other means or fasteners. The infrared-visible transmissive window 105 can be aligned with the laser light source 112 and the carbon nanotube thin film emitter 106 to maximize the amount of light that is transmitted through the infrared-visible transmissive window105. In an embodiment, infrared-visible transmissive window 105 is an optical grade window that is transparent to the wavelength of laser light 100 and is transparent at infrared wavelengths (e.g., 1 micron < < 25 microns). The thickness can be chosen such that the infrared-visible transmissive window 105 survives an atmosphere-vacuum pressure differential.

[0047] The carbon nanotube thin film emitter 106 includes a thin film of carbon nanotubes that is deposited on substrate 111. The carbon nanotubes 110 are aligned vertically, which means that they are all pointing in the same direction relative to the surface of the substrate 111. This alignment allows the carbon nanotubes to absorb laser light 100 more efficiently and to emit more thermal radiation 109. The layer of vertically aligned carbon nanotubes 110 can have a selected surface area on laser light source 112. This surface area allows the carbon nanotubes to interact with a selected amount of light in laser light 100and to emit more thermal radiation 109. The vertically aligned carbon nanotubes 110 are very good conductors of heat so that they quickly communicate heat. This rapid heat transfer allows the carbon nanotubes to reach high temperatures, which in turn allows them to emit more thermal radiation 109. The carbon nanotube thin film emitter 106 has a number of advantages over conventional thermal emission sources. The carbon nanotube thin film emitter 106 is very efficient at converting light into heat and can be operated at high temperatures without damage. The carbon nanotube thin film emitter 106 has a long lifetime and can be relatively inexpensive to manufacture.

[0048] The thermal radiation 109 produced by the carbon nanotube thin film emitter 106 is broadband so that it covers a wide range of wavelengths. The spectrum of the thermal radiation 109 is determined by the temperature of the carbon nanotube thin film emitter 106, as well as the properties of the carbon nanotubes themselves. The thermal radiation 109 can be used for a variety of applications, including spectroscopy, sensing, and imaging. The thermal radiation 109 can have a wavelength from 300 nm to 25000 nm.

[0049] Vertically aligned carbon nanotubes (VACNTs) are a type of carbon nanotube that are grown vertically on a substrate. They have a number of advantages, including: they are more stable and less likely to break; they can be grown to a high density, which makes them more efficient at emitting light; and they can be grown in a variety of shapes and sizes, which makes them versatile for different applications. VACNTs can be grown using chemical vapor deposition (CVD), wherein a carbon-rich gas is heated to a high temperature, and the carbon atoms are deposited on a substrate. The substrate can be made of silicon or metal, and it can be coated with a catalyst that helps to promote the growth of the nanotubes. The growth of VACNTs can be controlled by a number of factors, including the temperature of the substrate, the type of gas used, and the pressure of the gas. By controlling these factors, it is possible to grow VACNTswith a variety of properties. VACNTs can be about 100 nanometers in diameter, but they can be grown to a variety of sizes, in an embodiment, vertically aligned carbon nanotubes110 has a layer thickness that is at least 50 microns. Both lateral dimensions can be at most approximately 1 mm in some embodiments.

[0050] The substrate 111 is a thermally stable and chemically stable mechanical mount by which carbon nanotube thin film emitter 106 is mounted to the interior of vacuum chamber 104. The substrate 111 can be made of a variety of materials, including carbon, silicon, sapphire, and quartz. The thermal conductance of substrate111 can be as low as possibly attainable so that the device retains as much heat as possible. The lower the thermal conductance the more energy efficient the heating process is. In addition to retaining heat, a low thermal conductance smooths out any instabilities of the heating laser so that the emission more stable. In an embodiment, the substrate is a silicon nitride membrane with a thickness of 500 nm. In addition to a membrane structure, there are weak thermal legs (also known as weak thermal links) that connect the membrane to the bulk silicon substrate (background temperature). This structure greatly reduces the thermal conductance of the emitter. The thermal conductance was measured at room temperature to be approximately 20 μW / K, which provides a cooling time constant on the order of hundreds of milliseconds. The time constants can be tuned by lengthening the carbon nanotubes.

[0051] The substrate 111 can be chemically inert to prevent the carbon nanotube thin film emitter 106 from being corroded. The substrate 111 can be in the form of a wafer, a plate, or a rod. The substrate 111 can be smooth or rough. The substrate 111 can be coated with a variety of materials, including metals, oxides, and polymers. The coating can improve the adhesion of the carbon nanotube thin film emitter 106 to the substrate 111. The coating can also protect the carbon nanotube thin film emitter 106 from oxidation and corrosion. The substrate 111 can be mounted to the interior of vacuum chamber 104 in a variety of ways, including adhesive bonding, mechanical clamping, and welding. The method of mounting the substrate 111 provides the carbon nanotube thin film emitter 106 in good thermal contact with the substrate 111 so that the carbon nanotube thin film emitter 106 is not damaged during the mounting process. In an embodiment, substrate 111 can be made of a material or have a geometry that has high thermal resistance, such as silicon nitride membranes, tungsten, diamond, or the like. In an embodiment, substrate 111 is diamond. Although the thermal conductance of bulkdiamond (i.e., diamond having a thickness substantially greater than the thin diamond used as the substrate herein) is among the highest of known materials, the thermal conductance of the diamond substrate 211 is much lower than bulk diamond to prevent heat from being rapidly dissipated from the substrate. This can be achieved by reducing the thickness of a bulk substrate to a membrane thickness, e.g., less than or equal to 500 nm. By reducing the thickness to 500 nm or less, the thermal conductance is reduced by roughly three orders of magnitude from a typical bulk substrate (e.g., 500 pm thickness). The thickness of the thin diamond substrate retains the generated heat in the nanotubes and maintains high optical transmission and thermal properties (e.g., high melting point) of diamond.

[0052] The mounting post 107 can be a cylindrical rod that has a selected diameter, e.g., about 1 cm, and a selected length, e.g., about 5 cm. The mounting post 107 is attached to the carbon nanotube thin film emitter 106, e.g., by means a threaded connection or adhesive. The mounting post 107 provides a mechanical support for the carbon nanotube thin film emitter 106 and allows it to be positioned accurately relative to the off-axis parabolic mirror 103. The mounting post 107 also helps to dissipate heat from the carbon nanotube thin film emitter 106 as thermal radiation 109. The mounting post 107 is strong and rigid, which helps to keep the carbon nanotube thin film emitter 106 in place. The mounting post 107 is easy to attach to the carbon nanotube thin film emitter 106 and vacuum chamber 104.

[0053] The vacuum pump 108 is a device that removes gas from vacuum chamber 104. The vacuum pump 108 can be used to create a vacuum in the vacuum chamber 104, which occurs in operation of the carbon nanotube thermal emission source 200. There are many different types of vacuum pumps, e.g., a rotary vane pump. A rotary vane pump works by using a rotating vane to compress gas. The compressed gas is then expelled from the pump. Rotary vane pumps are typically very efficient and can create a vacuum of up to 10-6Torr. Another type of vacuum pump is a diffusion pump that can include a cooling baffle or liquid nitrogen trap to condense vapors and avoid contamination of carbon nanotube thin film emitter 106 with oils from the diffusion pump. Diffusion pumps can create a vacuum of up to 10- 10Torr.

[0054] The sample 117 is a material that is subjected to the thermal radiation 109 from the carbon nanotube thin film emitter 106. The sample 117 can be any material that is of interest to be analyzed, such as a biological sample, a chemical sample, or amaterial sample. The properties of the sample 117 can affect the spectral information that is produced by the radiation analyzer 118. For example, the chemical composition of the sample 117 will affect the wavelengths of light that are emitted by the sample 117. The temperature of the sample 117 will also affect the spectral information that is produced by the radiation analyzer 118. The radiation analyzer 118 can be used to analyze the spectral information to determine the chemical composition of the sample 117, the temperature of the sample 117, or other properties of the sample 117. In an embodiment, sample 117 includes an infrared absorbable analyte that absorbs infrared radiation in thermal radiation 109. The infrared absorbable analyte is a substance that absorbs infrared radiation. This absorption can be used to identify the analyte, or to measure its concentration.

[0055] The radiation analyzer 118 is a device that receives sample radiation 119 from sample 117, analyzes sample radiation 119, and produces spectral information about sample 117 from the analysis of sample radiation 119. The radiation analyzer 118 may be any type of device that can perform these functions, such as a spectrometer, a spectrograph, or a detector. The radiation analyzer 118 can be configured in a variety of ways, depending on the specific application. For example, the radiation analyzer 118 can be configured to analyze a specific wavelength range of radiation, or it may be configured to analyze a specific type of radiation, such as visible light, infrared light, or ultraviolet light. The radiation analyzer 118 can be configured to analyze a specific type of sample, such as a solid, a liquid, or a gas. The radiation analyzer 118 can be configured to analyze a specific property of a sample, such as its composition, its structure, or its temperature. The radiation analyzer 118 can be used in a variety of applications, such as in the analysis of materials, in the analysis of biological samples, in the analysis of environmental samples, and the like. The radiation analyzer 118 can be used in the development of new materials, in the development of new drugs, in the development of new technologies, and the like.

[0056] The sample radiation 119 is the radiation emitted by the sample 117 after it receives thermal radiation 109 from the carbon nanotube thermal emission source 200. The properties of the sample radiation 119 depend on the properties of the sample 117, the temperature of the sample 117, or the properties of the carbon nanotube thermal emission source 200. The sample radiation 119 can be a broadband spectrum of radiation, with a peak wavelength that depends on, e.g., the temperature of the sample 117. The intensity of the sample radiation 119 can depend on the temperature of thesample 117. The sample radiation 119 can be used to obtain spectral information about the sample 117, such as the chemical composition of the sample 117 or the temperature of the sample 117. The sample radiation 119 can be used in a variety of applications, such as in spectroscopy, in thermal imaging, and in non-destructive testing.

[0057] Carbon nanotube thermal emission source 200 can be made in various ways. It can be appreciated that carbon nanotube thermal emission source 200 includes a number of optical, electrical, or mechanical components, wherein such components can be interconnected and placed in communication (e.g., optical communication, electrical communication, mechanical communication, fluid communication, and the like) by physical, chemical, optical, or free-space interconnects. The components can be disposed on mounts that can be disposed on a bulkhead for alignment or physical compartmentalization. As a result, carbon nanotube thermal emission source 200 can be disposed in a terrestrial environment or space environment. Elements of carbon nanotube thermal emission source 200 can be formed from silicon, silicon nitride, and the like although other suitable materials, such as ceramic, glass, or metal can be used. According to an embodiment, the elements of carbon nanotube thermal emission source 200 are formed using 3D printing although the elements of carbon nanotube thermal emission source 200 can be formed using other methods, such as injection molding or machining a stock material such as block of material that is subjected to removal of material such as by cutting, laser oblation, and the like. Accordingly, carbon nanotube thermal emission source 200 can be made by additive or subtractive manufacturing. In an embodiment, elements of carbon nanotube thermal emission source 200 are selectively etched to remove various different materials using different etchants and photolithographic masks and procedures. The various layers thus formed can be subjected to joining by bonding to form carbon nanotube thermal emission source 200.

[0058] In an embodiment, a process for making and assembling the carbon nanotube thermal emission source 200 includes preparing substrate 111. The substrate 111 can be made of any material that is compatible with the carbon nanotubes, such as silicon, glass, or metal. The substrate 111 can be clean and free of any contaminants. The process can include growing vertically aligned carbon nanotubes 110 on the substrate 111. The carbon nanotubes 110 can be grown using a variety of methods, such as chemical vapor deposition, arc discharge, or laser ablation. The carbon nanotubes 110 can be grown in a uniform and dense array. The process can include patterning thecarbon nanotubes 110. The carbon nanotubes 110 can be patterned using a variety of methods, such as electron beam lithography, photolithography, or inkjet printing. The carbon nanotubes 110 can be patterned to form a desired pattern, such as a grid or a spiral. The carbon nanotube thermal emission source 200 can be assembled using a variety of methods, such as soldering, welding, or adhesive bonding. The carbon nanotube thermal emission source 200 can be assembled in a manner that ensures that the carbon nanotube thin film emitter 106 is in optical communication with the off-axis parabolic mirror 103. The process conditions for making and assembling the carbon nanotube thermal emission source 200 can vary depending on the specific materials and methods used. The temperature of the substrate 111 can be controlled to ensure that the carbon nanotubes 110 grow in a uniform and dense array. The pressure of the environment in which the carbon nanotubes 110 are grown can be controlled to avoid oxidation of the carbon nanotubes. The assembly of the carbon nanotube thermal emission source 200 can be done in a cleanroom environment to avoid contamination of the carbon nanotube thin film emitter 106.

[0059] In an embodiment, a process for making carbon nanotube thermal emission source 200 includes: depositing vertically aligned carbon nanotubes 110 on substrate 111 , e.g., according to methods described in US Patent No. 10,003,622 or US Patent No.7713589, the disclosure of each of which is incorporated by reference herein in its entirety. The process can include mechanically attaching vacuum chamber 104 to mounting post 107, e.g., with an epoxy. The process can include mechanically coupling mounting post 107 to vacuum chamber 104, e.g., with an epoxy, screw, or magnetic attachment. The process can include installing infrared-visible transmissive window 105 on an optical access exit port of vacuum chamber 104. The infrared-visible transmissive window 105 can be disposed on vacuum chamber 104 with a compatible seal such as an O-ring and vacuum compatible clamp. The process can include attaching vacuum pump 108 to a vacuum access port of vacuum chamber 104. The process can include disposing off-axis parabolic mirror 103 at its focal length from carbon nanotube thin film emitter 106 and arranging the face of off-axis parabolic mirror 103 perpendicular to the optical axis. The process can include disposing lens 102 at its focal length to be spaced apart from a front face of carbon nanotube thin film emitter 106, i.e., the exposed surface of vertically aligned carbon nanotubes 110 with the face of lens 102 perpendicular to the optical axis. The process can include aligning laser light 100 and plane mirror 101 such that the laser light 100 is focused from lens 102 through off-axis parabolic mirror 103 onto the exposedsurface of vertically aligned carbon nanotubes 110 of carbon nanotube thin film emitter 106.

[0060] In an embodiment, a process for making carbon nanotube thin film emitter 106 includes forming carbon nanotubes on a diamond substrate. Vertically aligned carbon nanotubes can be grown on the diamond substrate by physical vapor deposition (e.g., electron beam evaporation, sputtering, and the like) of a first support catalyst that includes a 4 nm thick layer of silicon nitride (SiNx); physical vapor deposition (e.g., electron beam evaporation, sputtering, and the like) of a second support catalyst that includes a 15 nm thick layer of aluminum nitride (AIN); physical vapor deposition (e.g., electron beam evaporation, sputtering and the like ) of a catalyst that includes a 2 nm thick layer of iron (Fe); and plasma enhanced chemical vapor deposition (PECVD) of vertically aligned carbon nanotubes under exemplary conditions such as: a total pressure / flow = 40 Torr / 500 seem, H2pressure / flow = 3.2 Torr / 42.5 seem, C2H4 / flow pressure = 0.8 Torr / sccm, Ar pressure / flow = 36 Torr / 452.5 seem, total flow = 500 seem, temperature = 800°C, 2.4 GHz RF power = 900 W, and processing time = 30 min.

[0061] Carbon nanotube thermal emission source 200 has numerous advantageous and unexpected benefits and uses. In an embodiment, a process for generating broadband thermal radiation with carbon nanotube thermal emission source 200 includes: providing a carbon nanotube thin film emitter; providing a vacuum chamber in which the carbon nanotube thin film emitter is disposed; providing an off-axis parabolic mirror in optical communication with the carbon nanotube thin film emitter; providing an infrared-visible transmissive window disposed on the vacuum chamber; communicating laser light to the carbon nanotube thin film emitter through the infrared-visible transmissive window; optically absorbing the laser light by the carbon nanotube thin film emitter; producing thermal radiation in response to the optical absorption of laser light; and communicating the thermal radiation to the parabolic surface of the off-axis parabolic mirror. In an embodiment, the carbon nanotube thin film emitter comprises vertically aligned carbon nanotubes. In an embodiment, the vacuum chamber has a pressure less than 10-3Torr. In an embodiment, the infrared-visible transmissive window is made of a material that is transparent to infrared and visible light. In an embodiment, the laser light has a wavelength of 150 nm to 10,000 nm. In an embodiment, the thermal radiation has a wavelength of 1000 nm to 10,000 nm. In an embodiment, the carbon nanotube thin film emitter is disposed on a substrate. In an embodiment, the substrate is made of a materialthat is thermally stable and chemically stable. In an embodiment, the carbon nanotube thin film emitter is optically interposed between the off-axis parabolic mirror and the substrate. In an embodiment, the substrate is mechanically interposed between the carbon nanotube thin film emitter and the vacuum chamber.

[0062] The carbon nanotube thermal emission source 200 can be used to generate broadband thermal radiation for a variety of applications, including spectroscopy, photothermal therapy, thermal imaging, and the like. To use the carbon nanotube thermal emission source 200, prepare the sample to be analyzed. The sample can be a solid, liquid, or gas. If the sample is a solid, it can be ground or dissolved in a solvent. If the sample is a liquid, it can be diluted. If the sample is a gas, it can be compressed. Dispose the sample in optical communication with the off-axis parabolic mirror 103 and the carbon nanotube thin film emitter 106. Disposed the carbon nanotube thin film emitter 106 in the vacuum chamber 104 that protects the carbon nanotube thin film emitter 106 from oxidation and contamination. The laser light source is turned on and produces laser light 100 that is focused on the carbon nanotube thin film emitter. The carbon nanotube thin film emitter absorbs the laser light and convert it into heat. The heat causes the carbon nanotubes to emit broadband thermal radiation 109. The broadband thermal radiation is collected by the off-axis parabolic mirror and reflected to the sample 117 and the radiation analyzer. The radiation analyzer analyzes the broadband thermal radiation or sample radiation 119 and produces spectral information about the sample 117. The spectral information can identify the chemical composition of the sample, determine the concentration of a particular substance in the sample, or measure the temperature of the sample 117.

[0063] In an embodiment, carbon nanotube thermal emission source 200 and generating broadband thermal radiation can include the properties, functionality, hardware, and process steps described herein and embodied in any of the following non- exhaustive list: a process (e.g., a computer-implemented method including various steps; or a method carried out by a computer including various steps); an apparatus, device, or system (e.g, a data processing apparatus, device, or system including means for carrying out such various steps of the process; a data processing apparatus, device, or system including means for carrying out varioussteps; a data processing apparatus, device, or system including a processor adapted to or configured to perform such various steps of the process); a computer program product (e.g., a computer program product including instructions which, when the program is executed by a computer, cause the computer to carry out such various steps of the process; a computer program product including instructions which, when the program is executed by a computer, cause the computer to carry out various steps); a computer-readable storage medium or data carrier (e.g., a computer-readable storage medium including instructions which, when executed by a computer, cause the computer to carry out such various steps of the process; a computer-readable storage medium including instructions which, when executed by a computer, cause the computer to carry out various steps; a computer-readable data carrier having stored thereon the computer program product; a data carrier signal carrying the computer program product);a computer program product including comprising instructions which, when the program is executed by a first computer, cause the first computer to encode data by performing certain steps and to transmit the encoded data to a second computer; or a computer program product including instructions which, when the program is executed by a second computer, cause the second computer to receive encoded data from a first computer and decode the received data by performing certain steps.

[0064] It should be understood that the calculations may be performed by any suitable computer system, such as that diagrammatically shown in FIG. 10. Data is entered into system 120 via any suitable type of user interface 121 , and may be stored in memory 122, which may be any suitable type of computer readable and programmable memory and is preferably a non-transitory, computer readable storage medium. Calculations are performed by processor 123, which may be any suitable type of computer processor and may be displayed to the user on display 124, which may be any suitable type of computer display.

[0065] Processor 123 may be associated with, or incorporated into, any suitable type of computing device, for example, a personal computer or a programmable logic controller. The display 124, the processor 123, the memory 122 and any associatedcomputer readable recording media are in communication with one another by any suitable type of data bus, as is well known in the art.

[0066] Examples of computer-readable recording media include non-transitory storage media, a magnetic recording apparatus, an optical disk, a magneto-optical disk, and / or a semiconductor memory (for example, RAM, ROM, etc.). Examples of magnetic recording apparatus that may be used in addition to memory 122, or in place of memory 122, include a hard disk device (HDD), a flexible disk (FD), and a magnetic tape (MT). Examples of the optical disk include a DVD (Digital Versatile Disc), a DVD-RAM, a CD- ROM (Compact Disc-Read Only Memory), and a CD-R (Recordable) / RW. It should be understood that non-transitory computer-readable media include all computer-readable media except for a transitory, propagating signal.

[0067] The carbon nanotube thermal emission source 200 has several advantages over conventional technology. The carbon nanotube thermal emission source 200 provides a broadband thermal radiation source that is stable and reliable. The carbon nanotube thermal emission source 200 can be compact and lightweight, making it easy to transport and use. The carbon nanotube thermal emission source 200 is relatively inexpensive to manufacture.

[0068] The carbon nanotube thermal emission source 200 has several advantages over other types of thermal emission sources. The carbon nanotube thermal emission source 200 can be more stable and reliable. Carbon nanotubes are very stable materials, and they do not degrade over time when maintained in non-oxidizing environs. This makes the carbon nanotube thermal emission source 200 a good choice for applications where long-term stability is important. Carbon nanotubes are very thin and light materials, which makes the carbon nanotube thin film emitter 106 easy to transport and use. Moreover, the carbon nanotube thin film emitter 106 has a high emissivity and can generate a large amount of thermal radiation. The carbon nanotube thin film emitter 106 is stable at high temperatures.

[0069] The carbon nanotube thermal emission source 200 can be used in a variety of applications, including spectroscopy, imaging, and sensing. The carbon nanotube thin film emitter 106 can be used to generate thermal radiation that can be used to analyze the spectral properties of samples. The carbon nanotube thin film emitter 106 can be used to generate thermal radiation that can be used to heat samples. The carbonnanotube thin film emitter 106 can be used to generate thermal radiation that can be used to pattern materials in photolithography. The carbon nanotube thin film emitter 106 can be used to generate thermal radiation that can be used to ablate materials. The carbon nanotube thin film emitter 106 can be used to generate thermal radiation that can be used to promote combustion.

[0070] The articles and processes herein are illustrated further by the following Examples, which are non-limiting.EXAMPLES

[0071] Example 1. A carbon nanotube thermal emission source 200 is fabricated according to the following steps: a substrate 111 is prepared by cleaning it with acetone and isopropanol. A thin film of carbon nanotubes 110 is grown on the substrate 111 by chemical vapor deposition. The carbon nanotube thin film emitter 106 is placed in a vacuum chamber 104. A laser light source 112 is used to heat the carbon nanotube thin film emitter 106. The thermal radiation 109 from the carbon nanotube thin film emitter 106 is transmitted by an infrared-visible transmissive window 105. The thermal radiation 109 is reflected by off-axis parabolic mirror 103 and received by a sample 1 13 that produces sample radiation 119 in response to receipt of thermal radiation 109. The sample radiation 119 is analyzed by a radiation analyzer 118. The results of the analysis show that the carbon nanotube thin film emitter 106 has a broadband emission spectrum with a peak wavelength of 10 μm. The emission spectrum from sample 117 is consistent with the absorption spectrum of carbonyl groups in sample 117. The carbon nanotube thermal emission source 200 is used to measure the concentration of formaldehyde in sample 117.

[0072] Example 2. Laser heating for carbon nanotube thermal emission.

[0073] Thermal emitters are a component for performing broadband infrared spectroscopy. This example described a laser-heated thermal emitter source based on vertically aligned carbon nanotubes (VACNTs). This thermal source overcomes technical deficiencies with conventional emitters such as tungsten and silicon carbide emitter (referred to as globar emitter) because VACNTs have an extremely high melting point>3000 K and near unity emissivity from visible through far-infrared. This example compares a VACNT source to a globar emitter in the mid- to far-infrared and.

[0074] Infrared spectroscopy is useful, inter alia, in material science, pharmaceutical research, gas detection , and remote sensing. For many of these, infrared source selection is a parameter that effects data quality and usefulness. For a given application, a number of desired source attributes may be involved. These may include spectral bandwidth, total power, source brightness, or dynamic properties including peak power or pulse width. For broadband spectroscopy, thermal emitters such as tungsten or silicon carbide (e.g., a globar emitter) are selected due to their spectral emission; however, such suffer from low spectral radiance compared to luminescent or coherent sources. As such, there remains a need for better sources with greater spectral brightness and more useful size of thermal emitters, e.g., for infrared spectroscopy. This example describes a thermal emitter with laser heating of VACNTs. VACNTs are selected as a thermal emitter because of their beneficial emission properties including near unity emissivity from the visible (300 nm) to far-infrared wavelengths (100 μm) and high melting point (in excess of 3400 K). In addition, VACNTs can be lithographically grown on a number of different material platforms which is advantageous for miniaturization.

[0075] VACNT-based microbolometer structures are near-ideal black-body devices, absorb light efficiently, and dissipate heat slowly through a substrate that is a mechanical support with a weak thermal link. Laser heating can determine the size of the emission area and can be advantageous when the source is reimaged (e.g., as in micro- FTIR). A carbon nanotube thermal emission source 200 is shown in FIG. 13a, wherein a fiber-based 532 nm light source is in optical communication with a variable attenuator. A flip mirror communicates the heating laser to a power meter that monitors the incident heating power. The heating laser is focused via a visible lens through a hole in an off- axis parabolic mirror (GAP), through an infrared transparent window (KBr), and onto a carbon nanotube device (FIG. 13b) that is disposed in a vacuum chamber and subjected to vacuum pressures. The VACNTs are heated while in vacuum because at elevated temperature, atmospheric gases are corrosive to the VACNTs. The carbon nanotubes convert the incident radiation to thermal emission. The GAP collimates thermal emission that is spatially filtered with a precision pinhole. The spatial filtering ensures that only the thermal emission area is included in the resulting beam.

[0076] The temperature of carbon nanotube thermal emission source 200 was measured with a disappearing filament pyrometer, and the operating temperature the source was approximately 2800 K to 3200 K. To compare with a globar emitter, carbon nanotube thermal emission source 200 was optically coupled through an FTIR into an infrared reflectance microscope. The confocal microscope provides approximately 4x magnification. The resolution was established using a precision pinhole with known diameter. A direct comparison of intensity was performed, wherein the spatial resolution enhancement of carbon nanotube thermal emission source 200 (FIG. 13a) was tested against a conventional globar emitter source in the mid- and far-infrared. Using a 300 μm diameter pinhole ( ~ 75 μm resolution at the sample), the relative intensity was acquired for carbon nanotube thermal emission source 200 and the globar emitter (FIG. 13b). The common mode features between carbon nanotube thermal emission source 200 and globar emitter are from atmospheric absorbances. The carbon nanotube thermal emission source 200 had roughly 50% greater intensity than the globar emitter, which is favorable and less than expected from Planck’s radiation law and attributable to collection optics, subject to engineering improvements. Reimaging capabilities of carbon nanotube thermal emission source 200 was compared with the globar emitter. The reflectance of a 100 μm x 100 μm gold square was performed for reflectance measurements with both sources relative to a bulk gold mirror. Any overfilling of the gold microstructure can result in a reflectance less than 1. Reflectance measurements on the 100 μm x 100 μm are presented in FIG. 13c. The reflectance data are displayed up to 15 μm because there was a large CO2 absorption centered near this wavelength. The globar emitter performed worse at resolving the reflectance of the microstructure, whereas carbon nanotube thermal emission source 200 provided correct results.

[0077] FIG. 13d shows a carbon nanotube thermal emission source 200 wherein VACNTs are grown on a diamond substrate, which does not absorb visible wavelengths of light and has a high melting point (> 4000 K). A laser communicates through the diamond and is absorbed by the VACNTs. As with the carbon nanotube thermal emission source 200 in FIG. 13a, carbon nanotube thermal emission source 200 shown in FIG. 13d includes a vacuum chamber in which carbon nanotube thin film emitter 106 is disposed. The VACNT emission exits through a diamond window and is collimated by a high numerical aperture (NA) Schwarzschild objective lens. Accordingly, carbon nanotube thermal emission source 200 shown in FIG. 13d can obtain a higher temperature than that of FIG. 13a, can collimate more photons, and can be more compact.

[0078] The following are incorporated by reference herein in their entirety:P. McArdle, F.-T. Huang, J. Yang, M.-W. Chu, S.-W. Cheong, and M. M. Qazilbash, “Orbital-selective metallicity in the valence-bond liquid phase of Li 2 RuO 3,” Phys. Rev. B, vol. 105, no. 24, p. 245148, Jun. 2022, doi: 10.1103 / PhysRevB.105.245148.G. N. Kalinkova, “Infrared spectroscopy in pharmacy,” Vibrational Spectroscopy, vol. 19, no. 2, pp. 307-320, Apr. 1999, doi: 10.1016 / S0924-2031(99)00017-X.X. Tan et al., “Non-dispersive infrared multi-gas sensing via nanoantenna integrated narrowband detectors,” Nat Commun, vol. 11 , no. 1 , p. 5245, Oct. 2020, doi: 10.1038 / s41467-020- 19085-1.“Libera: Understanding Earth’s Energy Budget,” Laboratory for Atmospheric and Space Physics. [Online], Available: https: / / lasp.colorado.edu / libera / J. Lehman, C. Yung, N. Tomlin, D. Conklin, and M. Stephens, “Carbon nanotubebased black coatings,” Applied Physics Reviews, vol. 5, no. 1 , p. 011103, Mar. 2018, doi: 10.1063 / 1.5009190.X. Wei, M.-S. Wang, Y. Bando, and D. Golberg, “Thermal stability of carbon nanotubes probed by anchored tungsten nanoparticles,” Science and Technology of Advanced Materials, vol. 12, no. 4, p. 044605, Aug. 2011 , doi: 10.1088 / 1468- 6996 / 12 / 4 / 044605.P. McArdle, C. Yung, N. Tomlin, J. Lehman, and M. Stephens, “Micro-DRIFTS for small area hyper-black spectroscopy,” Optics Express, vol. 31 , no. 26, 2023.

[0079] The processes described herein can be embodied in, and fully automated via, software code modules executed by a computing system that includes one or more general purpose computers or processors. The code modules can be stored in any type of non-transitory computer-readable medium or other computer storage device. Some or all the methods may alternatively be embodied in specialized computer hardware. In addition, the components referred to herein can be implemented in hardware, software, firmware, or a combination thereof.

[0080] Many other variations than those described herein can be apparent from this disclosure. For example, depending on the embodiment, certain acts, events, or functions of any of the algorithms described herein can be performed in a different sequence, can be added, merged, or left out altogether (e.g., not all described acts or events are necessary for the practice of the algorithms). Moreover, in certain embodiments, acts or events can be performed concurrently, e.g., through multi-threaded processing, interrupt processing, or multiple processors or processor cores or on other parallel architectures, rather than sequentially. In addition, different tasks or processes can be performed by different machines and / or computing systems that can function together.

[0081] Any logical blocks, modules, and algorithm elements described or used in connection with the embodiments disclosed herein can be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, and elements have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. The described functionality can be implemented in varying ways for each particular application, but such implementation decisions cannot be interpreted as causing a departure from the scope of the disclosure.

[0082] The various illustrative logical blocks and modules described or used in connection with the embodiments disclosed herein can be implemented or performed by a machine, such as a processing unit or processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A processor can be a microprocessor, but in the alternative, the processor can be a controller, microcontroller, or state machine, combinations of the same, or the like. A processor can include electrical circuitry configured to process computer-executable instructions. In another embodiment, a processor includes an FPGA or other programmable device that performs logic operations without processing computerexecutable instructions. A processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality ofmicroprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. Although described herein primarily with respect to digital technology, a processor may also include primarily analog components. For example, some or all of the signal processing algorithms described herein can be implemented in analog circuitry or mixed analog and digital circuitry. A computing environment can include any type of computer system, including, but not limited to, a computer system based on a microprocessor, a mainframe computer, a digital signal processor, a portable computing device, a device controller, or a computational engine within an appliance, to name a few.

[0083] The elements of a method, process, or algorithm described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module stored in one or more memory devices and executed by one or more processors, or in a combination of the two. A software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of non-transitory computer- readable storage medium, media, or physical computer storage known in the art. An example storage medium can be coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium can be integral to the processor. The storage medium can be volatile or nonvolatile.

[0084] While one or more embodiments have been shown and described, modifications and substitutions can be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation. Embodiments herein can be used independently or can be combined.

[0085] All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. The ranges are continuous and thus contain every value and subset thereof in the range. Unless otherwise stated or contextually inapplicable, all percentages, when expressing a quantity, are weight percentages. The suffix (s) as used herein is intended to include both the singular and the plural of the term that it modifies, thereby including at least one of that term (e.g., the colorant(s) includes at least one colorants). Option, optional, or optionally means that the subsequently described event or circumstance can or cannot occur, and that thedescription includes instances where the event occurs and instances where it does not. As used herein, combination is inclusive of blends, mixtures, alloys, reaction products, collection of elements, and the like.

[0086] As used herein, a combination thereof refers to a combination comprising at least one of the named constituents, components, compounds, or elements, optionally together with one or more of the same class of constituents, components, compounds, or elements.

[0087] All references are incorporated herein by reference.

[0088] The use of the terms "a," "an," and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. It can further be noted that the terms first, second, primary, secondary, and the like herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. It can also be understood that, although the terms first, second, etc. are, in some instances, used herein to describe various elements, these elements cannot be limited by these terms. For example, a first current could be termed a second current, and, similarly, a second current could be termed a first current, without departing from the scope of the various described embodiments. The first current and the second current are both currents, but they are not the same condition unless explicitly stated as such.

[0089] The modifier about used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., it includes the degree of error associated with measurement of the particular quantity). The conjunction or is used to link objects of a list or alternatives and is not disjunctive; rather the elements can be used separately or can be combined together under appropriate circumstances. / / PARTS LIST / / carbon nanotube thermal emission source 200 laser light 100 laser light source 112 plane mirror 101 lens 102 off-axis parabolic mirror 103 through aperture 113 aperture wall 114 primary surface 115 parabolic surface 116 vacuum chamber 104 infrared-visible transmissive window 105 carbon nanotube thin film emitter 106 thermal radiation 109 vertically aligned carbon nanotubes 110 substrate 111 mounting post 107 vacuum pump 108 sample 117 radiation analyzer 118 sample radiation 119 system 120user interface 121 memory 122 processor 123 display 124 generating broadband thermal radiation / / generates broadband thermal radiation

Claims

What is claimed is:

1. A carbon nanotube thermal emission source 200 for generating broadband thermal radiation, the carbon nanotube thermal emission source 200 comprising: an off-axis parabolic mirror 103 in optical communication with a laser light source 112 and a carbon nanotube thin film emitter 106 and that comprises a primary surface 115, a parabolic surface 116, and a through aperture 113 that is bounded by an aperture wall 114, such that the off-axis parabolic mirror 103 receives laser light 100 from the laser light source 112 in the through aperture 113, communicates the laser light 100 through the through aperture 113 to the carbon nanotube thin film emitter 106, receives thermal radiation 109 from the carbon nanotube thin film emitter 106 at the parabolic surface 116, and reflects the thermal radiation 109 from the parabolic surface 116; a vacuum chamber 104 in which is disposed the carbon nanotube thin film emitter 106 and that is in optical communication with the off-axis parabolic mirror 103 and in mechanical communication with the carbon nanotube thin film emitter 106 and that houses the carbon nanotube thin film emitter 106, receives the laser light 100 that is communicated in the through aperture 113 of the off-axis parabolic mirror 103 and an infrared-visible transmissive window 105, communicates the thermal radiation 109 produced from the carbon nanotube thin film emitter 106 to the parabolic surface 116 of the off-axis parabolic mirror 103 via the infrared-visible transmissive window 105, such that an interior of the vacuum chamber 104 in which the carbon nanotube thin film emitter 106 is disposed provides a pressure that is less than 10-3Torr and a gas environment that has a lower number density of oxidants that include oxygen than ambient air to avoid oxidation of the carbon nanotube thin film emitter 106 when the carbon nanotube thin film emitter 106 is subjected to heating by receipt of the laser light 100; the infrared-visible transmissive window 105 disposed on the vacuum chamber 104 and in mechanical communication with the vacuum chamber 104 and in optical communication with the off-axis parabolic mirror 103 and the carbon nanotube thin film emitter 106 and that receives the laser light 100 that is communicated through the through aperture 113 of the off-axis parabolic mirror 103, communicates the laser light 100 to the carbon nanotube thin film emitter 106, receives the thermal radiation 109 from the carbon nanotube thin film emitter 106, communicates the thermal radiation 109 to the parabolic surface 116 of the off-axis parabolic mirror 103, such that the vacuum chamber 104 incombination with the infrared-visible transmissive window 105 provides the pressure and the gas environment that avoids oxidation of the carbon nanotube thin film emitter 106 when the carbon nanotube thin film emitter 106 is subjected to heating by receipt of the laser light 100; the carbon nanotube thin film emitter 106 disposed in the vacuum chamber 104 and in mechanical communication with the vacuum chamber 104 and in optical communication with the off-axis parabolic mirror 103 and the infrared-visible transmissive window 105 and that comprises vertically aligned carbon nanotubes 110 and a substrate 111 , such that the vertically aligned carbon nanotubes 110 receives the laser light 100 from the vacuum chamber 104, optically absorbs the laser light 100, produces the thermal radiation 109 in response to the optical absorption of the laser light 100, and radiates the thermal radiation 109 to the parabolic surface 116 of the off-axis parabolic mirror 103 via communication through the infrared-visible transmissive window 105; the vertically aligned carbon nanotubes 110 disposed on the substrate 111 and disposed in the vacuum chamber 104 and in mechanical communication with the substrate 111 and the vacuum chamber 104 and in optical communication with the off- axis parabolic mirror 103 and the infrared-visible transmissive window 105 and that receives the laser light 100 from the off-axis parabolic mirror 103, optically absorbs the laser light 100, produces the thermal radiation 109 in response to the optical absorption of the laser light 100, radiates the thermal radiation 109 to the parabolic surface 116 of the off-axis parabolic mirror 103 via communication through the infrared-visible transmissive window 105; and the substrate 111 on which is disposed the vertically aligned carbon nanotubes 110 and that is disposed in the vacuum chamber 104 and in mechanical communication with the vertically aligned carbon nanotubes 110 and the vacuum chamber 104 and that provides a thermally stable, thermally insulating, and chemically stable mechanical mount by which the carbon nanotube thin film emitter 106 is mounted to the interior of the vacuum chamber 104, such that the vertically aligned carbon nanotubes 110 are optically interposed between the off-axis parabolic mirror 103 and the substrate 111 , and the substrate 111 is mechanically interposed between the vertically aligned carbon nanotubes 110 and the vacuum chamber 104.

2. The carbon nanotube thermal emission source 200 of claim 1 , further comprising the laser light source 112 in optical communication with the off-axis parabolic mirror 103 and the carbon nanotube thin film emitter 106 and that produces the laser light 100, communicates the laser light 100 to the carbon nanotube thin film emitter 106 through optical communication in the through off-axis parabolic mirror 103.

3. The carbon nanotube thermal emission source 200 of claim 1 , further comprising a plane mirror 101 in optical communication with the laser light source 112 and the off-axis parabolic mirror 103 and that receives the laser light 100 from the laser light source 112, reflects the laser light 100 to the off-axis parabolic mirror 103, such that the plane mirror 101 is optically interposed between the laser light source 112 and the off-axis parabolic mirror 103.

4. The carbon nanotube thermal emission source 200 of claim 1 , further comprising a lens 102 in optical communication with the laser light source 112, the off- axis parabolic mirror 103, and the carbon nanotube thin film emitter 106 and that receives the laser light 100 from the laser light source 112, focuses the laser light 100 into the through aperture 113 of the off-axis parabolic mirror 103 and onto the carbon nanotube thin film emitter 106, such that the lens 102 is optically interposed between the laser light source 112 and the off-axis parabolic mirror 103.

5. The carbon nanotube thermal emission source 200 of claim 1 , further comprising: the through aperture 113 disposed in the off-axis parabolic mirror 103 and in optical communication with the laser light source 112 and the carbon nanotube thin film emitter 106 and that is bounded by the aperture wall 114, extends through the off-axis parabolic mirror 103 from the primary surface 115 to the parabolic surface 116, receives the laser light 100, and communicates the laser light 100 through the off-axis parabolic mirror 103 to the carbon nanotube thin film emitter 106;the aperture wall 114 disposed in the off-axis parabolic mirror 103 and in optical communication with the laser light source 112 and the carbon nanotube thin film emitter 106 and that bounds the aperture wall 114, receives the laser light 100, and communicates the laser light 100 through the off-axis parabolic mirror 103 to the carbon nanotube thin film emitter 106; the primary surface 115 disposed on the off-axis parabolic mirror 103 and that is arranged at an acute angle to the parabolic surface 116 that receives and reflects the thermal radiation 109 from the carbon nanotube thin film emitter 106; and the parabolic surface 116 disposed on the off-axis parabolic mirror 103 and in optical communication with the carbon nanotube thin film emitter 106 and that comprises a parabolic shape and is arranged at the acute angle to the primary surface 115, receives the thermal radiation 109 from the carbon nanotube thin film emitter 106 and reflects the thermal radiation 109, such that rays of the thermal radiation 109 reflected from the parabolic surface 116 are parallel to one another.

6. The carbon nanotube thermal emission source 200 of claim 1 , further comprising a mounting post 107 on which is disposed the substrate 111 and that is disposed in the vacuum chamber 104 and in mechanical communication with the substrate 111 and the vacuum chamber 104 and that provides a thermally stable and mechanical mount by which the carbon nanotube thin film emitter 106 is mounted to the interior of the vacuum chamber 104, such that the mounting post 107 is mechanically interposed between the substrate 111 and the vacuum chamber 104.

7. The carbon nanotube thermal emission source 200 of claim 1 , further comprising a vacuum pump 108 disposed on the vacuum chamber 104 and in mechanical communication with the vacuum chamber 104 and in fluid communication with the carbon nanotube thin film emitter 106 and that evacuates the vacuum chamber 104 and removes gases in the vacuum chamber 104 to obtain the pressure that is less than 10-3Torr and the gas environment that has the lower number density of oxidants that include oxygen than ambient air to avoid oxidation of the carbonnanotube thin film emitter 106 when the carbon nanotube thin film emitter 106 is subjected to heating by receipt of the laser light 100.

8. The carbon nanotube thermal emission source 200 of claim 1 , further comprising a sample 117 in optical communication with the off-axis parabolic mirror 103 and the carbon nanotube thin film emitter 106 and that comprises an infrared absorbable analyte, receives the thermal radiation 109 reflected from the parabolic surface 116 of the off-axis parabolic mirror 103, and produces sample radiation 119 from absorption of the thermal radiation 109.

9. The carbon nanotube thermal emission source 200 of claim 8, further comprising a radiation analyzer 118 in optical communication with the sample 117 and that receives the sample radiation 119 from the sample 117, analyzes the sample radiation 119, and produces spectral information about the sample 117 from the analysis of the sample radiation 119.

10. The carbon nanotube thermal emission source 200 of claim 1 , wherein the thermal conductance of the substrate 111 is less than 50 μW / K.11 . The carbon nanotube thermal emission source 200 of claim 1 , wherein the substrate 111 comprises a silicon nitride membrane or a diamond membrane.

12. The carbon nanotube thermal emission source 200 of claim 1 , wherein the thickness of the substrate 111 from 500 nm to 200 nm.

13. The carbon nanotube thermal emission source 200 of claim 1 , wherein the substrate 111 comprises a bulk substrate; a membrane; and weak thermal legs thatconnect the membrane to a bulk silicon substrate, wherein the carbon nanotubes are disposed on the membrane.

14. The carbon nanotube thermal emission source 200 of claim 1 , wherein the substrate 111 has a cooling time constants that is from 100 ms to 900 ms.

15. A process for generating broadband thermal radiation with a carbon nanotube thermal emission source 200, comprising: providing a carbon nanotube thin film emitter; providing a vacuum chamber in which the carbon nanotube thin film emitter is disposed; providing an off-axis parabolic mirror in optical communication with the carbon nanotube thin film emitter; providing an infrared-visible transmissive window disposed on the vacuum chamber; communicating laser light to the carbon nanotube thin film emitter through the infrared-visible transmissive window; optically absorbing the laser light by the carbon nanotube thin film emitter; producing thermal radiation in response to the optical absorption of laser light; and radiating the thermal radiation to the parabolic surface of the off-axis parabolic mirror.

16. The process of 15, wherein the carbon nanotube thin film emitter comprises vertically aligned carbon nanotubes.

17. The process of 15, wherein the vacuum chamber has a pressure less than 10-3Torr.

18. The process of 15, wherein the infrared-visible transmissive window is made of a material that is transparent to infrared light and visible light.

19. The process of 15, wherein the laser light has a wavelength of 150 nm to 10,000 nm.

20. The process of 15, wherein the thermal radiation has a wavelength of 1000 nm to 10,000 nm.

21. The process of 15, wherein the carbon nanotube thin film emitter is disposed on a substrate.

22. The process of 15, wherein the substrate is made of a material that is thermally stable and chemically stable at a temperature at which the carbon nanotube thin film emitter 106 radiates the thermal radiation 109.

23. The process of 15, wherein the carbon nanotube thin film emitter is optically interposed between the off-axis parabolic mirror and the substrate.

24. The process of 15, wherein the substrate is mechanically interposed between the carbon nanotube thin film emitter and the vacuum chamber.

25. The process of 15, wherein the thermal conductance of the substrate 111 is less than 50 μW / K.

26. The process of 15, wherein the substrate 111 comprises a silicon nitride membrane or a diamond membrane.

27. The process of 15, wherein the thickness of the substrate 111 from 500 nm to 200 nm.

28. The process of 15, wherein the substrate 111 comprises a bulk substrate; a membrane; and weak thermal legs that connect the membrane to a bulk silicon substrate, wherein the carbon nanotubes are disposed on the membrane.

29. The process of 15, wherein the substrate 111 has a cooling time constants that is from 100 ms to 900 ms.

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