241 results about "Ultrashort laser" patented technology

Transcorneal and fiberoptic laser delivery systems and methods for the treatment of eye diseases wherein energy is delivered by wavelengths transparent to the cornea to effect target tissues in the eye for the control of intraocular pressure in diseases such as glaucoma by delivery systems both external to and within ocular tissues. External delivery may be effected under gonioscopic control. Internal delivery may he controlled endoscopically or fiberoptically, both systems utilizing femtosecond laser energy to excise ocular tissue. The femtosecond light energy is delivered to the target tissues to be treated to effect precisely controlled photodisruption to enable portals for the outflow of aqueous fluid in the case of glaucoma in a manner which minimizes target tissue healing responses, inflammation and scarring.

Various embodiments of a system described herein relate to micromachining materials using ultrashort visible laser pulses. The ultrashort laser pulses may be green and have a wavelength between about 500 to 550 nanometers in some embodiments. Additionally, the pulses may have a pulse duration of less than one picosecond in certain embodiments.

Systems and methods are provided for scribing wafers with short laser pulses so as to reduce the ablation threshold of target material. In a stack of material layers, a minimum laser ablation threshold based on laser pulse width is determined for each of the layers. The highest of the minimum laser ablation thresholds is selected and a beam of one or more laser pulses is generated having a fluence in a range between the selected laser ablation threshold and approximately ten times the selected laser ablation threshold. In one embodiment, a laser pulse width in a range of approximately 0.1 picosecond to approximately 1000 picoseconds is used. In addition, or in other embodiments, a high pulse repetition frequency is selected to increase the scribing speed. In one embodiment, the pulse repetition frequency is in a range between approximately 100 kHz and approximately 100 MHz.

A laser producing high energy ultrashort laser pulses comprises a normal dispersion segment, a gain segment, an anomalous dispersion segment with negligible nonlinearity and an effective saturable absorber arranged to form a laser cavity. Each segment is optically interconnected so that a laser pulse will propagate self-similarly therein. (A pulse that propagates in a self-similar manner is sometimes referred to as a “similariton.”) With this laser the limitations of prior art laser oscillators are avoided. Also provided are means for pumping the gain medium in the laser cavity, and means for extracting laser pulses from the laser cavity. The laser cavity is preferably a ring cavity. Preferably the laser is configured to achieve unidirectional circulation of laser pulses therein. This configuration is scalable to much higher pulse energy than lasers based on soliton-like pulse shaping.

High efficiency reflective volume Bragg gratings with chirped gratings recorded in photo-thermo-refractive glass having an absolute diffraction efficiency exceeding 95% in transmitting and reflecting modes are used to stretch and/or compress ultrashort laser pulses with high efficiency. Robustness, compactness, thermal and laser stability along with placement of multiple elements in the same space provides femtosecond laser system with high efficiency of stretching and re-compression of femtosecond pulses.

The invention pertains to medical devices, such as stents, having a surface and a first coating layer comprising a first polymer disposed on at least a portion of the surface, in which at least one cavity formed in the first coating layer. A biologically active material is deposited into the cavity, and a second coating layer comprising a second polymer is disposed over the biologically active material in the cavity. The cavity may be formed using an excimer laser or ultrashort laser to ablate the first coating layer, and the biologically active material may be deposited in the cavity using a picoliter dispensing system. Methods for making such medical devices are also disclosed.

Here is presented a versatile technique for machining of nanometer-scale features using tightly-focused ultrashort laser pulses. By the invention, the size of features can be reduced far below the wavelength of light, thus enabling nanomachining of a wide range of materials. The features may be extremely small (<20 nm) and are highly reproducible.

Ultrashort pulse laser processing bores, welds or cuts objects (work pieces) by converging ultrashort laser pulses by a lens on the objects (work pieces) positioned at the focus and heating small spots or narrow lines on the objects (work pieces). Shortage of a focal depth of the lens prevents the ultrashort pulse laser processing from positioning the object (a work piece) and forming a deep, constant-diameter cylindrical hole. Z-parameter is defined to be Z=2fcΔt/Δi², where Δt is a FWHM pulse width of the ultrashort pulse laser, Δi is a FWHM beam diameter of the ultrashort pulse, f is a focal length of the lens and c is the light velocity in vacuum. Selection of an optical system including a diffraction-type lens which gives the Z-parameter less than 1 (Z<1) prolongs the focal depth. Expansion of the focal depth facilitates the positioning of objects (work pieces) and enables the ultrashort pulse laser apparatus to bore a deep, constant-diameter cylindrical hole.

Various embodiments include a method of producing chemically pure and stably dispersed metal and metal-alloy nanoparticle colloids with ultrafast pulsed laser ablation. A method comprises irradiating a metal or metal alloy target submerged in a liquid with ultrashort laser pulses at a high repetition rate, cooling a portion of the liquid that includes an irradiated region, and collecting nanoparticles produced with the laser irradiation and liquid cooling. The method may be implemented with a high repetition rate ultrafast pulsed laser source, an optical system for focusing and moving the pulsed laser beams, a metal or metal alloy target submerged in a liquid, and a liquid circulating system to cool the laser focal volume and collect the nanoparticle products. By controlling various laser parameters, and with optional liquid flow movement, the method provides stable colloids of dispersed metal and metal-alloy nanoparticles. In various embodiments additional stabilizing chemical agents are not required.

A laser system using ultrashort laser pulses is provided. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and a spectrometer. Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and a SHG crystal. In yet another aspect of the present invention, a multiphoton intrapulse interference phase scan system and method characterize the spectral phase of femtosecond laser pulses. Fiber optic communication systems, photodynamic therapy and pulse characterization tests use the laser system with additional aspects of the present invention.

A laser pulse synthesis system is provided. A further aspect of the present system uses a phase-only modulator to measure ultrashort laser pulses. An additional aspect achieves interferences between split subpulses even though the subpulses have different frequencies. Yet another aspect of a laser system employs multi-comb phase shaping of a laser pulse. In another aspect, a laser system includes pulse characterization and arbitrary or variable waveform generation through spectral phase comb shaping.

The invention provides a versatile technique for machining of nanometer-scale features using tightly-focused ultrashort laser pulses. By the invention, the size of features can be reduced far below the wavelength of light, thus enabling nanomachining of a wide range of materials. The features may be extremely small, of nanometer size, and are highly reproducible.

A method for the laser reinforced direct bonding of two optical components having a respective bonding surface and a reinforced optical assembly made thereby are provided. The method includes a first step of assembling the two optical components by direct bonding of their respective bonding surface together, thereby defining a direct-bonded interface therebetween. The method further includes a second step of reinforcing the direct-bonded interface with a weld seam including at least one substantially continuous reinforcing weld line forming a dosed shape enclosing a sealed direct-bonded region. Each weld line is inscribed by focusing ultrashort laser pulses at the direct-bonding interface so as to generate non-linear optical phenomena inducing a localized junction between the two optical components. Advantageously, embodiments of the present invention provide reinforced optical assemblies exhibiting hermetic and mechanically resistant bonds over a large area as well as negligible alteration of their optical transmission properties.

The invention discloses a passive mode-locking fiber laser with a double-wavelength short pulse output. The invention has the characteristics of high stability, high efficiency, high power, high pulse repetition rate, synchronous passive laser impulse, single-line polarization, tunability, double wavelength and ultrashort pulse output. The ultrashort pulse fiber laser of the invention uses two polarization-preserving rare-earth doped (Er3+/ doped Yb3+) fibers as laser grain media, adopts a broadband polarization beam splitter spectrum and a broadband chirp polarization-preserving fiber grating and the like as cavity surface reflecting elements and chromatic dispersion compensation elements and utilizes a semiconductor saturable absorber as mode-locked elements and the like to achieve double-wavelength passive synchronous ultrashort pulse mode-locked fiber laser output. The passive mode-locking fiber laser with the double-wavelength short pulse output is a fiber laser with a novel structure of double-wavelength mode-locked ultrashort pulse output, which can achieve full-fiber.

The invention relates to a passive mode-locking ultrashort pulse all-fiber laser with a waveband of 2.0 microns and belongs to the field of a laser technology and nonlinear optics. The passive mode-locking ultrashort pulse all-fiber laser with the waveband of 2.0 microns mainly comprises a laser pumping source, a pumping combiner, thulium-doped or thulium-holmium-codoped rear earth doped fibers, a circulator, a saturable absorber, a laser beam splitter, an isolator, a fiber bragg grating, a polarization controller and the like. The thulium-doped or thulium-holmium-codoped rear earth doped fibers are used as a gain medium; the saturable absorber is used as a passive mode-locking device; and the output of an ultrashort laser pulse which is in the waveband of 2.0 microns and has high pulse energy is realized. Due to the adoption of the all-fiber structure design, the passive mode-locking ultrashort pulse all-fiber laser with the waveband of 2.0 microns has the advantages of simple structure, high environment stability and the like, and the industrialization application is easy to realize.

The invention discloses a totally positive dispersion cavity mode-locked all-fiber laser which is a fiber laser structure with high repetition rate and power, simple structure and high efficiency and is an all-fibermode-locked ultrashort laser pulse laser with stable environment and novel structure. The all-fiber laser takes rare earth doped fiber as a laser gain medium, works in a totally positive dispersion area, uses a polarizing beam splitter to split light, uses a band-pass type long-period fiber grating filter for wavelength selectivity of a mode-locked laser centre and spectral filtering light pulse compression of mode-locked laser and takes a semiconductor saturable absorber as fiber laser structures. The totally positive dispersion cavity mode-locked all-fiber laser has picosecond and femtosecond light impulse length polarizing laser output and lasers with the wavelengths longer than 1 micrometer and can be used for pumping-detecting ultrafast light physical experiments or the environmental monitoring and the microwave photonics and biophysics detection of a molecular system, double-wavelength pumping-detecting ultrafast light physical experiments, frequency-combining light radiation generation, coherent anti-Stokes Raman scattering microscopy, micromachining, and the like by being amplified by a high-power fiber amplifier.

The invention provides a single ultrashort laser pulse contrast measuring device. The optical path of the device is described as follows: the measured parallel laser beam passes through a first half-transparent half mirror and is changed into transmission light and reflection light; the transmission light sequentially passes through a right-angle prism, a first reflector, a second-harmonic crystal, an optical filter and a half-wave plate; the reflection light passes through the second reflector; two beams of light enter to a sum-frequency crystal at a phase matching angle to generate three-order self-relation signals which are filtered by a first filter plate and a knife edge; the light is divided into two beams by a second half-transparent half mirror, wherein one beam of light sequentially passes through a first attenuation plate, a first cylindrical lens and a second filter plate and then enters a first CCD (Charge Coupled Device), and the other beam of light sequentially passes through a barrier plate, a second attenuation plate, a second cylindrical lens and a third filter plate and then enters a second CCD; and both CCDs test a main peak where the three-order self-relation signals are located and the area out of the main peak. The invention can obtain continuous relevant signal intensity distribution information and the single ultrashort laser pulse contrast tested by the device can be about 106.

An adjustable astigmatic elongated beam spot may be formed from a laser beam having ultrashort laser pulses and/or longer wavelengths to machine substrates made of a variety of different materials. The laser beam may be generated with pulses having a pulse duration of less than 1 ns and/or having a wavelength greater than 400 nm. The laser beam is modified to produce an astigmatic beam that is collimated in a first axis and converging in a second axis. The astigmatic beam is focused to form the astigmatic elongated beam spot on a substrate, which is focused on the substrate in the first axis and defocused in the second axis. The astigmatic elongated beam spot may be adjusted in length to provide an energy density sufficient for a single ultrashort pulse to cause cold ablation of at least a portion of the substrate material.