A terahertz spectrum test device and system includes a femtosecond fiber laser configured to generate a pump light and a probe light. The pump light excites a terahertz transmitter to generate terahertz waves which are transmitted to a sample suspension device to irradiate a suspended to-be-tested sample, and the probe light is directly transmitted to a terahertz detector. The terahertz detector receives the terahertz waves transmitted from the sample suspension device, and then transmits the terahertz waves and the probe light together to a signal processing circuit to obtain a corresponding terahertz time-domain spectrum. By adoption of the terahertz spectrum test device and system, the to-be-tested sample need not be fixed with a clamp or other instruments, so that terahertz waves will not irradiate to the instrument used for fixing the to-be-tested sample during a terahertz spectrum test, which may otherwise affect the test result.

The present application provides a terahertz spectrum measurement system and a method for analyzing a terahertz spectrum of a substance, wherein the terahertz spectrum measurement system comprises: two terahertz quantum cascade lasers with their emission ports arranged oppositely; and a vacuum hood arranged between the emission ports of two terahertz quantum cascade lasers. The terahertz spectrum measurement system and the method for analyzing a terahertz spectrum of a substance realize a separate terahertz dual frequency comb while retaining the advantages of the on-chip dual frequency comb system, which solves the problem that the on-chip dual frequency comb cannot directly measure the terahertz spectra of substances.

The present application provides a terahertz spectrum measurement system and a method for analyzing a terahertz spectrum of a substance, wherein the terahertz spectrum measurement system comprises: two terahertz quantum cascade lasers with their emission ports arranged oppositely; and a vacuum hood arranged between the emission ports of two terahertz quantum cascade lasers. The terahertz spectrum measurement system and the method for analyzing a terahertz spectrum of a substance realize a separate terahertz dual frequency comb while retaining the advantages of the on-chip dual frequency comb system, which solves the problem that the on-chip dual frequency comb cannot directly measure the terahertz spectra of substances.

An apparatus configured to perform in-situ, real-time, noninvasive monitoring of fermentation processes at a location remote from the fermenter/bioreactor in a laboratory or an industrial environment is described. The apparatus enables monitoring and detection of CO.sub.2 in fermentation-based processes with high precision, continuously and in real time from the exhaust pipe or exhaust bypass of any size or type of fermenter/bioreactor or pipe diameter.

A photo-acoustic gas sensor using a method for modulating the wavelength of the laser radiation, the modulation being obtained via judicious use of an electric current, called the generation current, which pumps the one or more laser sources, and is configured to cause the one or more laser sources to operate in pulsed mode, and of a current, called the base current, which takes non-zero values between each laser pulse with a lower magnitude than the magnitude of the generation current, the magnitude of base current being modulated so that the one or more laser sources emit, into the cell, light radiation having a wavelength that varies periodically about a central wavelength so as to take, at regular intervals, a value specifically suitable for the excitation of a gas to be detected, whereby an interaction between the light radiation and the gas to be detected contained in the cell induces the generation of acoustic waves at a resonant frequency of the cell.

A system includes a first laser beam including a pulsed laser emanating from the instrument propagates in the air, wherein the first lase beam is tuned to the wavelength at which a target chemical absorbs, its pulses bringing molecules to an excited state, a second laser beam used to probe target chemicals by transient absorption spectroscopy, wherein the second laser beam is pulsed or continuous, and a detector.

Disclosed herein is a spectroscopy device incorporating a mid-infrared laser. In one particular embodiment a spectroscopy device is provided including: a substrate; a single mode laser positioned on the substrate; a single mode detector positioned opposite to the single mode laser on the substrate. A gap is formed between the single mode laser and the single mode detector and a substance is positioned in the gap. The single mode laser is configured to output a tunable narrow wavelength of radiation towards the detector and when the single mode laser outputs a wavelength of radiation overlapping one of the substance's rotational-vibrational energy levels, the substance at least partially absorbs the radiation. The single mode detector is configured to measure the amount of narrow wavelength radiation that is not absorbed by the substance between the single mode detector and the single mode laser.

The present invention relates to an analysis apparatus adapted to analyze a measurement target component contained in a sample by irradiating a measurement cell into which the sample is introduced with pulse-oscillated light, whereby suppressing reduction in wavelength resolution without shortening the pulse width. The analysis apparatus includes multiple light sources adapted to produce pulse oscillations, a light detector adapted to detect light emitted from the light source and transmitted through the measurement cell, and a signal separation part adapted to separate, from a light intensity signal obtained by the light detector, signals corresponding to a part of pulses from the light sources.

The present disclosure describes a method and apparatus of measuring dynamic light scattering of a sample. In an embodiment, the apparatus includes a platen, a light source underneath the platen and configured to emit emitted light through the platen and into the sample, collector optics underneath the platen and configured to capture scattered light, and an optical absorber configured to be in contact with the sample, configured to absorb transmitted light, and configured to redirect reflected light away from the collector optics. In an embodiment, the method includes depositing a sample on a platen, emitting emitted light from a light source underneath the platen through the platen and into the sample, capturing via collector optics underneath the platen scattered light, contacting the sample with an optical absorber, absorbing via the absorber transmitted light, and redirecting via the absorber reflected light away from the collector optics.

A system includes a first laser beam including a pulsed laser emanating from the instrument propagates in the air, wherein the first lase beam is tuned to the wavelength at which a target chemical absorbs, its pulses bringing molecules to an excited state, a second laser beam used to probe target chemicals by transient absorption spectroscopy, wherein the second laser beam is pulsed or continuous, and a detector.