Tokyo Gas Company Limited

Other

Anritsu Corporation

Kiyoji Uehara

Hideo Tai

Hiroaki Tanaka

Takashi Ueki

Masayuki Matsuura

Naohiro Yoshida

Haruo Nagai

Tomoyuki Kikugawa

Masafumi Aizawa

An isotopomer absorption spectral analyzing apparatus and its method for precisely measuring the isotope ratio by substantially equalizing the absorption signal levels of different species of isotopes. In an isotopomer absorption spectral analyzing apparatus, a sample cell ( ) capable of providing optical paths of different optical lengths is installed, optical beams A, B are caused to enter the sample cell ( ) and travel along paths of different optical lengths, thereby determining the abundance ratio between species of isotopes in molecules from the ratio between intensities of signals corresponding to the species of isotopes.

Isopotomer absorption spectral analyzer and its method

A gas detection device employs a tunable wavelength laser, modulated about an absorption line of a gas to be detected. By measuring the ratio of the fundamental to the second harmonic of the modulation frequency, the detection is independent of the optical path length. This permits an aimable device in which a laser beam is directed toward a remote surface, reflected thereby, and the reflected beam focused upon a detector. The presence of the gas to be detected in the space between the device and the reflective surface is thereby determined.

Gas detection device

A light source has a tunable wavelength single mode semiconductor laser. The laser outputs a single mode laser beam having a wavelength tuned in accordance with a drive current and emits, for an object to be detected, at least a first laser beam having a first wavelength which is absorbed by a gas to be detected and a second laser beam having a second wavelength which is not absorbed by the gas to be detected. A controller switches the drive current having a predetermined value corresponding to the first or second wavelength at a predetermined period and supplies the drive current to the laser and controls the drive current having the predetermined value corresponding to the first or second wavelengths so that the first or second laser beams are alternately output from the laser with substantially the same power while the first and second wavelengths are maintained. A light-receiving unit receives first and second response light components generated when the first and second laser beams emitted alternately from the laser are incident on the object to be detected and outputs electrical signals corresponding to received light amounts of the first and second response light components. A signal processor receives the electrical signals from the light-receiving unit and processes the presence/absence of gas detection in accordance with a difference between the received light amounts of the first and second response light components.

Differential absorption laser radar gas detection apparatus having

A dual-wavelength laser apparatus includes a laser emitting a laser beam consisting of two wavelength components, a methane cell for controlling and equalizing gains of the two wavelength components, a cavity length modulator including a piezoelectric element for periodically modulating the cavity length of the laser, and a feedback circuit for controlling the modulation center such that the sum of outputs of the two modulated wavelength components is kept substantially constant. The feedback circuit includes a detector for detecting a laser output, a lock-in amplifier for detecting and amplifying an output from the detector, an integrator for integrating an output from the lock-in amplifier, and a high-voltage amplifier for generating a bias voltage set by the integrator.

Dual-wavelength laser apparatus

Growing community of inventors

Tokyo, Japan

Kiyoji Uehara