A terahertz spectrometer includes: a terahertz-wave emitter and a terahertz receiver elements. The terahertz wave generated by means of generating beat frequency corresponding to the difference between two rapidly tunable continuous wave lasers. Having a difference in time between the interrogating signal and the reference signal at the receiver end side, which corresponds to intermediate frequency (IF), not centered around the baseband, i.e. zero Hertz. The offset step size of the intermediate frequency from zero Hertz is linearly correlated to the position of the interrogated object position.

Detector data representative of an intensity of light that impinges on a detector after being emitted from a light source and passing through a gas over a path length can be analyzed using a first analysis method to obtain a first calculation of an analyte concentration in the volume of gas and a second analysis method to obtain a second calculation of the analyte concentration. The second calculation can be promoted as the analyte concentration upon determining that the analyte concentration is out of a first target range for the first analysis method.

A compact mmW spectroscopy cell system for detecting volatile organic compounds (compounds) in a gas. The system includes a gas collection chamber, an input buffer cavity for receiving the gas from the gas collection chamber, pumping devices to pass the gas from the buffer cavity to an absorption cell and maintain pressure, and a transceiver connected to the cell. The transceiver interrogates the absorption cell filled with the gas by passing a high frequency electromagnetic signal and sweeping the signal to generate an absorption spectra which is compared to a spectroscopy database for detecting the compounds in the gas. The absorption cell, collection chambers, and pumping devices are fabricated with standard CMOS processing techniques at chip and wafer scale. The transceiver bonded to the absorption cell with chip scale integration.

A terahertz spectrometer includes: a terahertz-wave emitter and a terahertz receiver elements. The terahertz wave generated by means of generating beat frequency corresponding to the difference between two rapidly tunable continuous wave lasers. Having a difference in time between the interrogating signal and the reference signal at the receiver end side, which corresponds to intermediate frequency (IF), not centered around the baseband, i.e. zero Hertz. The offset step size of the intermediate frequency from zero Hertz is linearly correlated to the position of the interrogated object position.

A vibrational sum frequency generation spectroscopy system with pulse shaping is provided. The pulse shaping provides tunable NIR-Shaped light pulses based on user input parameters which may be specified to customize the system for different experimental and testing conditions or needs.

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.

Embodiments herein describe spectroscopy systems that use an unmodulated reference optical signal to mitigate noise, or for other advantages. In one embodiment, the unmodulated reference optical signal is transmitted through the same vapor cell as a modulated pump optical signal. As such, the unmodulated reference optical signal experiences absorption by the vapor, which converts laser phase noise to amplitude noise like the other optical signals passing through the vapor cell. In one embodiment, the unmodulated reference optical signal has an optical path in the gas cell that is offset (or non-crossing) from the optical path of the modulated pump optical signal. The unmodulated reference optical signal allows removal or mitigation of the noise on the other optical signal.

An assembly (14) for analyzing a sample (15) includes a detector assembly (18); a tunable laser assembly (10); and (iii) a laser controller (10F). The detector assembly (18) has a linear response range (232) with an upper bound (232A) and a lower bound (232B). The tunable laser assembly (10) is tunable over a tunable range, and includes a gain medium (10B) that generates an illumination beam (12) that is directed at the detector assembly (18). The laser controller (10F) dynamically adjusts a laser drive to the gain medium (10B) so that the illumination beam (12) has a substantially constant optical power at the detector assembly (18) while the tunable laser assembly (10) is tuned over at least a portion of the tunable range.

This invention can be embodied in a mobile device for food identification and quantification with both a spectroscopic sensor and a camera. It can be a handheld food scanner, food probe, smart food utensil, utensil attachment, removable component of a smart watch or wrist band, phone component, or phone accessory. It can provide information on types and quantities of food (and nutrients, chemicals, and microorganisms in that food). It can be wirelessly linked with a wearable device to comprise a system for monitoring and modifying a person's food consumption habits.

A vibrational sum frequency generation spectroscopy system with pulse shaping is provided. The pulse shaping provides tunable NIR-Shaped light pulses based on user input parameters which may be specified to customize the system for different experimental and testing conditions or needs.