Abstract: Improved cavity enhanced optical spectroscopy is provided by appropriate per-mode averaging of measured vs. desired frequencies. By using this information to control the optical path length of the cavity, the frequency comb defined by the cavity at which measurements are performed can be substantially stabilized vs. perturbations such as changes in gas sample pressure.

Abstract: Improved cavity enhanced absorption spectroscopy is provided using a piecewise tunable laser by using a lookup table for laser tuning that is configured specifically for this application. In preferred embodiments this is done in combination with a laser control strategy that provides precise wavelength determination using cavity modes of the instrument as a reference.

Abstract: Improved correction of optical absorption spectroscopy results for trace gas detection is provided by correcting for species crosstalk (and other environmental effects) on a per-frequency basis. Analyte concentrations are then determined by curve fitting to the corrected absorption spectrum. This is in marked contrast to the conventional approach of first performing a curve fit to determine analyte concentrations, then correcting the analyte concentrations to account for species crosstalk and other environmental effects. In some embodiments, the number of parameters for the per-frequency corrections are automatically determined from the data (e.g., using a LASSO regression).

Abstract: Improved cavity enhanced absorption spectroscopy is provided using a piecewise tunable laser by using a lookup table for laser tuning that is configured specifically for this application. In preferred embodiments this is done in combination with a laser control strategy that provides precise wavelength determination using cavity modes of the instrument as a reference.

Abstract: Improved optical absorption spectroscopy of species having broad spectral features is provided by choosing frequencies to cover the spectral feature(s) of interest, where the frequencies are slightly adjusted as needed to avoid narrow spectral features from interfering chemical species (i.e., clutter). The resulting clutter avoidance provides improved optical spectroscopy of species having broad spectral features.

Abstract: Improved cavity enhanced absorption spectroscopy is provided using a piecewise tunable laser by using a lookup table for laser tuning that is configured specifically for this application. In preferred embodiments this is done in combination with a laser control strategy that provides precise wavelength determination using cavity modes of the instrument as a reference.

Abstract: Improved cavity enhanced absorption spectroscopy is provided using a piecewise tunable laser by using a lookup table for laser tuning that is configured specifically for this application. In preferred embodiments this is done in combination with a laser control strategy that provides precise wavelength determination using cavity modes of the instrument as a reference.

Abstract: Improved optical absorption spectroscopy of species having broad spectral features is provided by choosing frequencies to cover the spectral feature(s) of interest, where the frequencies are slightly adjusted as needed to avoid narrow spectral features from interfering chemical species (i.e., clutter). The resulting clutter avoidance provides improved optical spectroscopy of species having broad spectral features.

Abstract: Improved cavity enhanced absorption spectroscopy is provided using a piecewise tunable laser by using a lookup table for laser tuning that is configured specifically for this application. In preferred embodiments this is done in combination with a laser control strategy that provides precise wavelength determination using cavity modes of the instrument as a reference.

Abstract: Interleaved data acquisition in optical spectroscopy is used to provide interference correction for time-varying interference. Measurements at a reference frequency are used to provide an estimate of the interference. These reference measurements are interleaved with the remaining measurements in order to provide estimates of the interference vs. time at relevant times. The interference being corrected can be spectrally structured or unstructured.

Abstract: Interleaved data acquisition in optical spectroscopy is used to provide interference correction for time-varying interference. Measurements at a reference frequency are used to provide an estimate of the interference. These reference measurements are interleaved with the remaining measurements in order to provide estimates of the interference vs. time at relevant times. The interference being corrected can be spectrally structured or unstructured.

Abstract: Optical spectrometer apparatus, systems, and methods for analysis of carbon-14 including a resonant optical cavity configured to accept a sample gas including carbon-14, an optical source configured to deliver optical radiation to the resonant optical cavity, an optical detector configured to detect optical radiation emitted from the resonant cavity and to provide a detector signal; and a processor configured to compute a carbon-14 concentration from the detector signal, wherein computing the carbon-14 concentration from the detector signal includes fitting a spectroscopic model to a measured spectrogram, wherein the spectroscopic model accounts for contributions from one or more interfering species that spectroscopically interfere with carbon-14.

Abstract: For cavity enhanced optical spectroscopy, the cavity modes are used as a frequency reference. Data analysis methods are employed that assume the data points are at equally spaced frequencies. Parameters of interest such as line width, integrated absorption etc. can be determined from such data without knowledge of the frequencies of any of the data points. Methods for determining the FSR index of each ring-down event are also provided.

Abstract: Optical spectrometer apparatus, systems, and methods for analysis of carbon-14 including a resonant optical cavity configured to accept a sample gas including carbon-14, an optical source configured to deliver optical radiation to the resonant optical cavity, an optical detector configured to detect optical radiation emitted from the resonant cavity and to provide a detector signal; and a processor configured to compute a carbon-14 concentration from the detector signal, wherein computing the carbon-14 concentration from the detector signal includes fitting a spectroscopic model to a measured spectrogram, wherein the spectroscopic model accounts for contributions from one or more interfering species that spectroscopically interfere with carbon-14.

Abstract: For cavity enhanced optical spectroscopy, the cavity modes are used as a frequency reference. Data analysis methods are employed that assume the data points are at equally spaced frequencies. Parameters of interest such as line width, integrated absorption etc. can be determined from such data without knowledge of the frequencies of any of the data points.

Abstract: Compositions comprising photobleachable organic materials can be bleached by 193 nm light, and brought back to their original state by stimuli after exposure. (reversible photobleaching). We use these compositions in art-known contrast enhancement layers and as a part of a photoresist, especially in optical lithography processes for semiconductor fabrication. They may comprise polymers such as organo-silicon polymers, polymers comprising polymers of aromatic hydroxyl compounds such as phenol and naphthol such as phenol formaldehyde polymers and naphthol formaldehyde polymers styrene polymers and phenolic acrylate polymers or cyclic materials comprising: where the radicals “R” and “Y” represent organo, or substituted organo moieties, Structures I, II, and III represent basic organic skeletons and can be unsubstituted or substituted in any available position with any one or combinations of multiple substituents.

Abstract: Compositions comprising photobleachable organic materials can be bleached by 193 nm light, and brought back to their original state by stimuli after exposure. (reversible photobleaching). We use these compositions in art-known contrast enhancement layers and as a part of a photoresist, especially in optical lithography processes for semiconductor fabrication. They may comprise polymers such as organosilicon polymers, polymers comprising polymers of aromatic hydroxyl compounds such as phenol and naphthol such as phenol formaldehyde polymers and naphthol formaldehyde polymers styrene polymers and phenolic acrylate polymers or cyclic materials comprising: where the radicals “R” and “Y” represent organo, or substituted organo moieties, Structures I, II, and III represent basic organic skeletons and can be unsubstituted or substituted in any available position with any one or combinations of multiple substituents.

Abstract: A method and system is provided for computing lithographic images that may take into account non-scalar effects such as lens birefringence, resist stack effects, tailored source polarizations, and blur effects of the mask and the resist. A generalized bilinear kernel is formed, which is independent of the mask transmission function, and which may then be treated using a decomposition to allow rapid computation of an image that includes such non-scalar effects. Weighted pre-images may be formed from a coherent sum of pre-computed convolutions of the dominant eigenfunctions of the generalized bilinear kernel with the appropriate mask polygon sectors. The image at a point may be formed from the incoherent sum of the weighted pre-images over all of the dominant eigenfunctions of the generalized bilinear kernel. The resulting image can then be used to perform model-based optical proximity correction (MBOPC).

Abstract: An optical beam transformation system includes a first and a second optical element, each of which has a non-reentrant surface. The system transforms a substantially non-uniform optical input beam (such as a Gaussian) to a substantially uniform output beam. The first and second optical elements are arranged in either a Keplerian or Galilean configuration. The aspheric surface of the second optical element is related to the aspheric surface of the first optical element by a ray-tracing function that maps substantially all of an input light beam that is incident on the first optical element to a collimated output light beam that is output from the second optical element. Preferably, the output light beam has a Fermi-Dirac intensity distribution, and the ray-tracing function maps the input light beam to the output beam out to the (1/e)6 intensity radius of the input light beam.

Abstract: An optical beam transformation system includes a first and a second optical element, each of which has a non-reentrant surface. The system transforms a substantially non-uniform optical input beam (such as a Gaussian) to a substantially uniform output beam. The first and second optical elements are arranged in either a Keplerian or Galilean configuration. The aspheric surface of the second optical element is related to the aspheric surface of the first optical element by a ray-tracing function that maps substantially all of an input light beam that is incident on the first optical element to a collimated output light beam that is output from the second optical element. Preferably, the output light beam has a Fermi-Dirac intensity distribution, and the ray-tracing function maps the input light beam to the output beam out to the (1/e)6 intensity radius of the input light beam.