William Marsh Rice University

United Technologies Corporation

Texas Instruments Corporation

Other

Frank K Tittel

Gerard Wysocki

William L Wilson, Jr

William L Nighan

Michael C Smayling

Stephen So

J Patrick Frantz

Gabor T Szabo

Joseph R Cavallaro

Anatoliy A Kosterev

Robert F Curl

Motoi Kido

Roland A Sauerbrey

A novel low-power and compact laser spectroscopic sensor is described herein. Embodiments of the disclosed sensor utilize state-of-the-art microprocessors and digital processing techniques to reduce power consumption and integrate functions into a small device. In particular, novel software methods are disclosed which allow the use of low-power microprocessors which draw no more than about 0.02 W of power. Such low-power enables long battery life and allows embodiments of the sensor to be used in portable applications. In addition, the system architecture and methods described in this disclosure allow a single integrated embedded processor to control all the subsystems necessary for a laser spectroscopic sensor further reducing sensor size and power consumption. In addition, a power efficient method of calibrating a photoacoustic laser spectroscopic sensor is disclosed.

Integrated embedded processor based laser spectroscopic sensor

An apparatus comprising a laser source configured to emit a light beam along a first path, an optical beam steering component configured to steer the light beam from the first path to a second path at an angle to the first path, and a diffraction grating configured to reflect back at least a portion of the light beam along the second path, wherein the angle determines an external cavity length. Included is an apparatus comprising a laser source configured to emit a light beam along a first path, a beam steering component configured to redirect the light beam to a second path at an angle to the first path, wherein the optical beam steering component is configured to change the angle at a rate of at least about one Kilohertz, and a diffraction grating configured to reflect back at least a portion of the light beam along the second path.

Fast wavelength tuning techniques for external cavity lasers

A widely tunable, mode-hop-free semiconductor laser operating in the mid-IR comprises a QCL laser chip having an effective QCL cavity length, a diffraction grating defining a grating angle and an external cavity length with respect to said chip, and means for controlling the QCL cavity length, the external cavity length, and the grating angle. The laser of claimwherein said chip may be tuned over a range of frequencies even in the absence of an anti-reflective coating. The diffraction grating is controllably pivotable and translatable relative to said chip and the effective QCL cavity length can be adjusted by varying the injection current to the chip. The laser can be used for high resolution spectroscopic applications and multi species trace-gas detection. Mode-hopping is avoided by controlling the effective QCL cavity length, the external cavity length, and the grating angle so as to replicate a virtual pivot point.

Piezo activated mode tracking system for widely tunable mode-hop-free external cavity mid-IR semiconductor lasers

The present invention provides methods and apparatus for flexible and reproducible control of quantum cascade laser frequency scans having short (nanosecond) pulse excitations. In accordance with a preferred embodiment of the invention, a method of digital frequency control for pulsed quantum cascade lasers includes digitally synthesizing a sub-threshold current, converting the sub-threshold current to analog form, and generating laser pulses. Preferably, the sub-threshold current is synchronized to the laser pulses.

Frequency scanning pulsed laser having synchronously set subthreshold current

A multiple image photolithography system includes a radiation source ( ) projecting electromagnetic radiation along a path. A reticle cartridge ( ) is located in the path of the projected radiation. The cartridge ( ) includes a photomask ( ) located in the path of the projected radiation and a Fabry-Perot interferometer ( ) located in the path of the projected radiation. A radiation-sensitive material ( ) is located in the path of the projected radiation such that the projected radiation encounters the reticle cartridge ( ) before the projected radiation encounters the radiation-sensitive material ( ).

Multiple image photolithography system and method

A phase shifting method uses a special interferometer in which the illuminating beam is divided into two or more components and the mask is irradiated from both sides. The pattern to be transferred onto the wafer (the mask) is generated on an optically transmissive substrate by appropriately combining reflective, transparent and absorptive areas. The optical paths of the beams illuminating the back side and the front side of the mask (that will be called transmitted and reflected beams respectively) are chosen so that the phase of the two beams is different by approximately an odd multiple of .pi. radians at the surface of the mask. The combined beams are projected onto the target wafer by suitable optics. The phase difference between the illuminating beams reduces the edge blurring that results from diffraction effects. This steepens the slope of the intensity profile at the edge of the features making it possible to achieve smaller feature sizes in the microlithographic replication without using those phase shifting elements of the conventional phase shifting method which made mask fabrication difficult. As a consequence of the lack of the phase shifting layers, the wavelength range of the method of this invention can easily be extended towards shorter wavelengths, and, further, the new mask is less vulnerable to optical damage. The additional freedom that the phase relation and intensity of the beams can be varied continuously allows for optimization that can lead to improved resolution, compared to conventional phase shifting techniques.

Interferometric phase shifting method for high resolution

A transverse electrically excited gas laser comprises a mixture of rare gases and a fluorine donor at selected partial pressures so as to permit UV and/or visible rare gas-halide laser oscillation at two or more wavelengths simultaneously.

Multiple wavelength excimer laser

An improved electric discharge XeF excimer laser employs a reaction gas mixture containing NF.sub.3 and F.sub.2 in proportions that tailor the kinetics of the electrochemical reactions in order to achieve a substantial increase in power.

Two-halogen donor mixture for XeF (C.fwdarw.A) laser

A xenon fluoride (C.fwdarw.A) laser operating in the visible region is improved by the use of a synthesized buffer gas containing at least two components that combine to provide kinetic properties that are different from those of any single-component buffer gas.

Growing community of inventors

Houston, TX, United States of America

Frank K Tittel