3128 results about "Optical pathlength" patented technology

A prism assembly using only cholesteric layers for splitting input light into component light beams and individually directing the component light beams to modulating devices. Liquid coupling prism assembly components to produce reduced stress index and pathlength matched prism assemblies from low tolerance components. Pathlength matching in beam splitting devices using a variety of optical component shapes and beam splitting layer materials. Various prism assembly designs using cholesteric layers supported on planar and / or on optical component diagonals.

A method and an arrangement are provided for scalable confocal interferometry for distance measurement, for 3-D detection of an object, for OC tomography with an object imaging interferometer and at least one light source. The interferometer has an optical path difference not equal to zero at each optically detected object element. Thus, the maxima of a sinusoidal frequency wavelet, associated with each detected object element, each have a frequency difference Δf_Objekt. At least one spectrally integrally detecting, rastered detector is arranged to record the object. The light source preferably has a frequency comb, and the frequency comb differences Δf_Quelle are changed in a predefined manner over time in a scan during measuring. In the process, the frequency differences Δf_Quelle are made equal to the frequency difference Δf_Objekt or equal to an integer multiple of the frequency differences Δf_Objekt at least once for each object element.

A tunable optical source comprises a laser diode and an external optical feedback device. The feedback device has a waveguiding portion fabricated at least in part out of a glass material having both organic and inorganic components. A control device is provided for controlling the refractive index of the glass material so as to change the wavelength of feedback to the laser diode. The glass material may for example have thermo-optic properties and the control device might then be a heating device for heating the glass material. The feedback device can have more than one portion, a second portion for example having controllable coupling characteristics for coupling optical radiation into or out of the feedback device. It also preferably has a portion for controlling optical path length in the feedback device.

A constant pathlength multi-assay plate cover for multi-assay plates, comprising, a flat top side and a flat bottom side, the bottom side having solid cylindrical projections of equal length extending downwardly from the flat bottom side, wherein each cylindrical projection is centered about the optical axis passing through a corresponding sample well of a multi-assay plate, thereby eliminating the meniscus and evaporation effects.

In projection exposure of isolated pattern such as a contact hole, in order to increase the depth of focus a coherence reducing member is disposed on a Fourier transform plane in an image-forming optical path between a mask and a sensitized base, so that coherence is reduced between image-forming beams respectively passing through a plurality of different, concentric regions around the optical axis of the projection optical system on the Fourier transform plane. The coherence reducing member may be a polarization state control member for making a difference in polarization state, a member for making a difference in optical path length, or space filters with different shapes.

Semi-integrated external cavity diode laser (ECDL) designs including integrated structures comprising a gain section, phase control section, and optional modulator section. Each integrated structure includes a waveguide that passes through each of the sections. A mirror is defined in the structure to define one end of a laser cavity. A reflective element is disposed generally opposite a rear facet of the gain section, forming an external cavity therebetween. A tunable filter is disposed in the external cavity to effectuate tuning of the laser. During operation, a modulated drive signal is provided to the phase control section. This modulates an optical path length of the laser cavity, which produces an intensity (amplitude) modulation in the laser output. A detector is employed to produce a feedback signal indicative of the intensity modulation that is used for tuning the laser in accordance with a wavelength locking servo loop. Upon passing through the modulator section, an optical signal is modulated with data.

A method and apparatus for reducing speckle uses polarization averaging. A polarizing beam splitter divides a first polarized laser output into a second polarized laser output and a third polarized laser output. A plurality of mirrors creates an optical path difference between the second and third polarized laser outputs. The optical path difference is at least about a coherence length for the first polarized laser output. The second and third polarized laser outputs are combined into a fourth laser output, which illuminates a depolarizing screen. If a human eye or an optical system having a intensity detector views the depolarizing screen, the eye or the intensity detector will detect reduced speckle, which results from uncorrelated speckle patterns created by the second polarized laser output and the third polarized laser output. A first alternative embodiment of the invention functions without the optical path difference being at least about the coherence length. In the first alternative embodiment, a piezoelectric transducer varies an optical path length by at least about a half wavelength of the first polarized laser output. By varying the optical path length by a sufficient frequency, the eye or the intensity detector will detect the reduced speckle. A second alternative embodiment combines two orthogonally polarized laser outputs, from two lasers, into a combined laser output. The combined laser output illuminates the depolarizing screen. A third alternative embodiment rotates the first laser output with a rotation frequency to form a rotating polarized laser output, which illuminates the depolarizing screen.

In annealing a non-single crystal silicon film through the use of a linear laser beam emitted by a YAG laser of a light source, it is the object of the present invention to prevent heterogeneity in energy caused by an optical interference produced in the linear laser beam from having an effect on the silicon film. The laser beam is divided by a mirror 604 shaped like steps into laser beams which have an optical path difference larger than the coherence length of the laser beam between them. The divided laser beams are converged on an irradiate surface 611 by the action of a cylindrical lens array 605 and a cylindrical lens 606 to homogenize the energy of the laser beam in the length direction and to determine the length of the linear laser beam. On the other hand, the laser beams divided by a cylindrical lens array 607 are converged on the irradiate surface 611 by a cylindrical lens 608 and a doublet cylindrical lens 609 to homogenize the energy in the width direction of the laser beam and to determine the width of the linear laser beam. Interference fringes parallel to the width direction of the linear laser beam disappears in the linear laser beam by the action of a mirror 604 shaped like steps. If the silicon film is annealed by the linear laser beam while the linear laser beam is being shifted in the width direction of the linear laser beam, the silicon film is remarkably homogenized as compared with a conventional silicon film.

A light-emitting optical cavity light-emitting diode device, comprising:a) a substrate;b) a reflective electrode formed over the substrate;c) an unpatterned light-emitting layer formed over the reflective electrode;d) a transparent electrode formed over the unpatterned light-emitting layer;e) one or more different optical spacers, defining at least two different optical path lengths, are formed in different locations over the substrate, between the reflective electrode and the transparent electrode; andf) a low-index layer formed over the transparent electrode.

Optical waveguide devices are disclosed which utilize an optical waveguide having a waveguide bend therein with a width that varies adiabatically between a minimum value and a maximum value of the width. One or more connecting members can be attached to the waveguide bend near the maximum value of the width thereof to support the waveguide bend or to supply electrical power to an impurity-doped region located within the waveguide bend near the maximum value of the width. The impurity-doped region can form an electrical heater or a semiconductor junction which can be activated with a voltage to provide a variable optical path length in the optical waveguide. The optical waveguide devices can be used to form a tunable interferometer (e.g. a Mach-Zehnder interferometer) which can be used for optical modulation or switching. The optical waveguide devices can also be used to form an optical delay line.

An apparatus and a method of measuring an optical path difference in a sensing interferometer. Light from a source is directed in the sensing interferometer. The light reflected from the sensing interferometer is splitted into first and second beams respectively directed into two reference interferometers having optical path differences greater than the coherence length of the source and such that the optical signals are in quadrature. The intensities of the light transmitted by the reference interferometers and recombined light reflected from the reference interferometers are detected for measuring the optical path difference in the sensing interferometer. Additional light sources allow for correction of internal perturbations and absolute measurement of the optical path difference in the sensing interferometer.

A semi-transmissive film is provided underneath a transparent electrode of an organic EL element. The optical length of the interval between the upper surface of the semi-transmissive film and the lower surface of a counter electrode serving as a reflective layer is configured such that this interval functions as a microresonator for selecting light having a specific wavelength. Further, a light-shielding film is provided in a position corresponding to the peripheral portion of the semi-transmissive film, so as to prevent light having a different color from being ejected due to non-uniformity in the optical length.

An optical subassembly includes a high speed ceramic substrate having cavity containing an array of photodetectors, and a glass or silicon window for covering the cavity and forming a hermetic seal. A retainer is attached to the window for direct or indirect attachment to a fiber. The hermetic seal protects the device from moisture and other environmental conditions. The window has an index of refraction higher than air that effectively increases the optical pathlength sufficient while maintaining an acceptable coupling efficiency between the optoelectronic device and a fiber. This provides increased spacing within which to place and interconnect components within the cavity on the substrate. In alternate embodiments, the window is decoupled from direct contact with the retainer via a metal frame or ring. Decoupling the window from direct contact with the retainer helps prevent cracking of the window due to mismatches in the coefficients of thermal expansion between the window and the retainer.

A method of measuring a selected physical parameter at a location within a region of interest comprises the steps of: launching optical pulses at a plurality of preselected interrogation wavelengths into an optical fiber (1) deployed along the region of interest, reflectors (20, 21, 2n) being arrayed along the optical fiber (1) to form an array (9) of sensor elements, the optical path length between the said reflectors (2) being dependent upon the selected parameter; detecting the returned optical interference signal for each of the preselected wavelengths; determining from the optical interference signal the absolute optical path length (L) between two reflectors (2) at the said location; and determining from the absolute optical path length (L) the value of the selected parameter at the said location; wherein the step of determining the absolute optical path length (L) comprises carrying out a process in which the phase difference between the interference signals for a pair of the preselected wavelengths is estimated using an estimated value for the optical path length (L), the estimated phase difference is used to estimate the phase at each of those wavelengths, and the phase thus obtained is used to revise the estimated value for the optical path length (L), the process being repeated for some or all remaining wavelength pairs in sequence, on the basis of the optical path length (L) estimated for the immediately preceding pair in the sequence, thereby to progressively revise the optical path length (L) until it is know to a desired level of accuracy.

The invention provides an all-fiber testing device for testing the polarization crosstalk of an optical device. The all-fiber testing device comprises a wide-spectrum light source (501), a polarizer (511), a to-be-tested polarizing device (522), an optical path correlator (530), a difference detector (550) and a photoelectric signal conversion and signal recording device (560), wherein the wide-spectrum light source (501) is connected with the to-be-tested optical fiber device (522) through the polarizer (511) and a first rotary connector (521) and is connected with the optical path correlator (530) with a polarization beam splitting Michelson structure through a second rotary connector (523); and the optical path correlator (530) is connected with the polarization difference detector (550) through a third rotary connector (541) and is connected with an interference signal detecting and processing device (560). The all-fiber testing device has the advantages of small size, high measurement accuracy, high temperature and vibration stability and the like, so that the all-fiber testing device is widely applied to high-accuracy measurement and analysis of the polarization performance of the optical device.

Disclosed are photometric methods and devices for determining optical pathlength of liquid samples containing analytes dissolved or suspended in a solvent. The methods and devices rely on determining a relationship between the light absorption properties of the solvent and the optical pathlength of liquid samples containing the solvent. This relationship is used to establish the optical pathlength for samples containing an unknown concentration of analyte but having similar solvent composition. Further disclosed are methods and devices for determining the concentration of analyte in such samples where both the optical pathlength and the concentration of analyte are unknown. The methods and devices rely on separately determining, at different wavelengths of light, light absorption by the solvent and light absorption by the analyte. Light absorption by the analyte, together with the optical pathlength so determined, is used to calculate the concentration of the analyte. Devices for carrying out the methods particularly advantageously include vertical-beam photometers containing samples disposed within the wells of multi-assay plates, wherein the photometer is able to monitor light absorption of each sample at multiple wavelengths, including in the visible or UV-visible region of the spectrum, as well as in the near-infrared region of the electromagnetic spectrum. Novel photometer devices are described which automatically determine the concentration of analytes in such multi-assay plates directly without employing a standard curve.

The invention discloses a multi-wavelength high-sensitivity online monitor of multi-component NH3 and H2O based on semiconductor laser absorption spectroscopy. It contains host chassis and open long-path system. Equip power receptacle, switch, fiber connector and data transmission interface. It is characterized in that: there are near-infrared semiconductor laser, semiconductor laser controller, phase-locked amplifier, signal generator, data collecting and controlling module and infrared detector in host chassis which is connected with field optical system by fiber. Open optical system contains send-receive optical telescope and multielement reflector array. Optical telescope has input and output fiber couplers. The device realizes simultaneous testing of gas multi-component by using multi-wavelength and frequency division multi-signal detecting technique.

The invention discloses a distributed optical fiber sensing device based on a chaotic laser coherence method, and a measurement method of the distributed optical fiber sensing device. Chaotic laser light which is emitted from a chaotic laser is divided into detection light and reference light; the detection light is amplified by a light amplifier and then emitted into a sending optical fiber through an optical circulator, and a backward Brillouin scattering light signal is generated in the optical fiber; the Brillouin scattering light signal is amplified by the light amplifier, de-noised by a tunable light filter and then emitted into an optical fiber coupler; the optical length of the reference light is regulated by a variable light delay line, and interferes with the backward Brillouin scattering light signal which is generated by the detection light at different positions in the sensing optical fiber in the optical fiber coupler; an interference beat frequency signal is detected by a photoelectrical detector; and Brillouin gain spectra at different lengths are obtained through a data acquisition device and a signal processing device and then output to a display device, so strain or temperature sensing detection is realized.

The invention provides a device and a method for improving polarization crosstalk measurement performance of an optical device. The device comprises a wide spectrum light source (301), a polarizer (311), a polarization device to be tested (632), an optical path correlator (640) and a polarization crosstalk detection and signal recording device (150), wherein the wide spectrum light source (301) is connected with the optical device to be tested (632) by the polarizer (311) and a first rotation connector (631) and then is connected with the optical path correlator (640) by a second rotation connector (633). By the device and the method, noise amplitude can be greatly suppressed, the sensitivity of polarization crosstalk measurement is improved, the dynamic range of polarization crosstalk measurement is expanded, and the device and the method are widely used for high-precision measurement and analysis on polarization performance of the optical device.

Interferometric scanning method(s) and apparatus for measuring rotationally and non-rotationally symmetric test optics either having aspherical surfaces or that produce aspherical wavefronts. A spherical or partial spherical wavefront is generated from a known origin along an optical axis. The test optic is aligned with respect the optical axis and selectively moved along it relative to the known origin so that the spherical wavefront intersects the test optic at the apex of the aspherical surface and at radial positions where the spherical wavefront and the aspheric surface intersect at points of common tangency. An axial distance, ν, and optical path length, p, are interferometrically measured as the test optic is axially scanned by the spherical wavefront where ν is the distance by which the test optic is moved with respect to the origin and p is the optical path length difference between the apex of an aspherical surface associated with the test optic and the apex of the circles of curvature that intersect the aspherical surface at the common points of tangency. Coordinates of the aspherical surface are calculated wherever the circles of curvature have intersected the aspherical surface and in correspondence with the interferometrically measured distances, ν and p. Afterwards, the shape of the aspheric surface is calculated. Where the test optic comprises a refracting optic a known spherical reflecting surface is provided upstream of the refracting optic for movement along the optical axis and a known wavefront is made to transit the refracting optic, reflects from the known spherical surface, again transits the refracting optic traveling towards the known origin after which the interferogram is formed. In another aspect of the invention, a spherical reference surface is provided to form a Fizeau that is used to generate phase information for measuring spheres, mild aspheres, and multiple mild aspheres.

Provided is an optical image measuring apparatus forming a three-dimensional image based on tomographic images of an object, acquired at various depths even when the object moves during measurement. Including a half mirror (6) for dividing a light beam signal light (S) and reference light (R), a frequency shifter (8), a reference mirror (9) and a piezoelectric element (9A) used to change an optical path length of the reference light (R), CCDs (21, 22) for receiving interference light beams (L) resulting from interference light produced by superimposing the signal light (S) and the reference light (R) on each other by the half mirror (6) and outputting detection signals, an image forming portion for forming tomographic images based on the detection signals, a measurement depth calculating means (53), and an image processing portion (57). Forming a three-dimensional image or the like based on the arranged tomographic images.

An ophthalmic photographing apparatus includes: an interference optical system including a splitter that splits light, emitted from a measurement light source, into measurement light and reference light, and synthesizing the measurement light reflected on an eye with the reference light to guide the synthesized light to a detector; a driving part that moves an optical member arranged in the optical path to adjust an optical-path difference between the measurement light and the reference light; an image obtaining part that obtains a tomographic image of a fundus or an anterior segment based on a light receiving signal output from the detector; and a driving control unit that controls driving of the driving part to locate the optical member in a predetermined position corresponding to either a photographing mode for photographing the tomographic image of the fundus or a photographing mode for photographing the tomographic image of the anterior segment.

The invention discloses an optical measurement method and devices used for measuring film thickness and refractive index. Light emitted out of a broadband light source generates an interference signal through interference structure, the spectrum information of the interference signal is detected and the fourier transform of the spectrum information is carried out, thus obtaining the optical path difference information of two optical paths which can generate the interference signal. Under known refractive index, a sample is arranged in an interference arm in the same type and is measured again, and the film thickness can be obtained by comparing the information of twice optical path differences. If the refractive index is unknown, the film is required to be rotated by an angle, and the refractive index and the thickness of the film can be worked out by the measurement of a third time. The optical measurement method and the devices used for measuring film thickness and refractive index adopt an optical method and have no damage to the sample; the resolution is micro level and the measured range can achieve millimeter level. Furthermore, the sample is not required to be strictly attached onto a sample platform; meanwhile, the information processing method is simple, and the information of the thickness and the refractive index of transparent or half-transparent film can be conveniently obtained in real time.

The invention discloses a apparatus and method for adjustable multiple reflection optical absorption, which adopts the principle of multiple reflection to design a optical absorbing pool; light beam multiple reflects by main reflector and two auxiliary reflectors so as to effectively accrete the length of detecting optical path in a small spacing. The multiple reflection optical absorbing pool has compact structure and can do alternative measurement to sample spectrum and background spectrum.