International Business Machines Corporation

Princeton University

Eric J Zhang

William M Green

Gerard Wysocki

Chu Cheyenne Teng

Lionel Tombez

Chi Xiong

Cheyenne Teng

Jeng-Bang Yau

Bucknell Chapman Webb

Eric Peter Lewandowski

William M J Green

Matthias Dittberner

Techniques regarding selectively tuning the operating frequency of superconducting Josephson junction resonators are provided. For example, one or more embodiments described herein can comprise a method that can include chemically altering a Josephson junction of a Josephson junction resonator via a plasma treatment. The method can also comprise selectively tuning an operating frequency of the Josephson junction resonator based on a property of the plasma treatment.

Selective chemical frequency modification of Josephson junction resonators

A method for assessing spectroscopic sensor accuracy, includes building an a priori simulation of generalized etalon drift. A spectroscopic sensor is tested to determine use parameters. A specific drift model is generated by applying the determined use parameters to the built a priori simulation of generalized etalon drift. The specific drift model is analyzed to determine whether the spectroscopic sensor is satisfactory.

System and method for assessing spectroscopic sensor accuracy

A method is provided for Fourier domain dynamic correction of optical fringes in a laser spectrometer. The method includes Fourier transforming a background spectrum contaminated with the optical fringes to obtain baseline fringes in a frequency domain. The method includes partitioning the baseline fringes in the frequency domain to obtain partitioned baseline fringes. The method includes reconstructing the partitioned baseline fringes as separate spectra. The method includes constructing a fitting model to approximate the background spectrum by assigning a first and a second free parameter to each of partitioned baseline fringe components to respectively allow for drift and amplitude adjustments during a fitting of the fitting model. The method includes applying the fitting model to a newly acquired spectrum to provide an interpretation of the newly acquired spectrum having a reduced influence of spectral contamination on concentration retrieval.

Fourier domain dynamic correction method for complex optical fringes in laser spectrometers

A generalized feed-forward method for accurate tunable laser absorption spectroscopy includes generating a laser beam. The generated laser beam is directed down a reference path and a test/sample path. One or more parameters are extracted from the reference path. The one or more parameters, extracted from the reference path, are used as feed-forward, to adjust spectral analysis of the test/sample path to detect a composition and/or concentration of an analyte gas within the test/sample path. The extraction of the one or more parameters from the reference path and the spectral analysis of the test/sample path are performed substantially concurrently.

Feed-forward spectral calibration methodology for line-scanned tunable laser absorption spectroscopy

An on-chip spectroscopic sensor includes a tunable diode laser. A laser driver for drives the tunable diode laser. An analyte test cavity receives a chemical sample and exposes the received chemical sample to light from the tunable diode laser. An optical detector detects light emerging from the analyte test cavity as a result of the laser exposure. A spectral analyzer determines a spectrum of the emerging light, matches and removes one or more known optical fringe patterns from the determined spectrum, and determines a composition or concentration of the chemical sample from the optical fringe pattern-removed spectrum.

On-chip spectroscopic sensors with optical fringe suppression

A tunable diode laser absorption spectroscopy device includes a tunable diode laser. A laser driver is configured to drive the diode laser and ramp it within a particular frequency range. An analyte gas container, a reference gas container, and a fringe generating device are configured to receive the laser therethrough. An optical detector is configured to detect the laser after it has passed through the analyte gas container and/or the reference gas container, and the in-line fringe generating device. An acquisition card is configured to sample an output of the optical detector. A spectral analyzer is configured to receive output data from the acquisition card, determine a spectrum of the output data, decouple the fringe spectrum from the measured spectrum, calibrate the spectrum based on an expected ideal spectrum of both the fringe and reference gas, and determine a composition of the analyte based on the calibrated spectrum.

Tunable diode laser absorption spectroscopy with corrected laser ramping nonlinearities

A method is provided for Fourier domain dynamic correction of optical fringes in a laser spectrometer. The method includes Fourier transforming a background spectrum contaminated with the optical fringes to obtain baseline fringes in a frequency domain. The method includes partitioning the baseline fringes in the frequency domain using bandpass filtering to obtain partitioned baseline fringes. The method includes reconstructing the partitioned baseline fringes as separate spectra using an inverse Fourier transform. The method includes constructing a fitting model to approximate the background spectrum by assigning a first and a second free parameter to each of partitioned baseline fringe components to respectively allow for drift and amplitude adjustments during a fitting of the fitting model. The method includes applying the fitting model to a newly acquired spectrum to provide an interpretation of the newly acquired spectrum having a reduced influence of spectral contamination on concentration retrieval.

Provided herein are techniques for improved optical absorption measurements in the presence of time-varying etalons. In one aspect, a method for dynamic etalon fitting for adaptive background noise reduction in an optical sensor is provided. The method includes the steps of: obtaining a zero-gas spectrum measured using the optical sensor; obtaining an analyte gas spectrum of a target trace gas measured using the optical sensor; comparing the zero-gas spectrum and the analyte gas spectrum using fit parameters that compensate for drifting etalons in the optical sensor; and dynamically extracting the drifting etalons from the analyte gas spectrum to retrieve concentration of the target trace gas.

Ensuring stable, precise, and accurate optical absorption spectroscopic trace gas concentration measurements in the presence of time-varying etalons

Disclosed herein is a system for detecting the presence of an chemical in a sample comprising a laser light source for generating a beam of light; a beam splitter that is operative to split the beam of light into a first beam of light and a second beam of light; a reference cell and a first recording device that are operative to receive the first beam of light; where the first recording device is downstream of the reference cell; a resonator that is operative to receive the second beam of light via a coupler; where the resonator contains the sample that contains the chemical; a phase modulator and a second recording device that lie downstream of the resonator and are operative to receive the second beam of light.

Growing community of inventors

Yonkers, NY, United States of America

Eric J Zhang