Gas Analysis  Gas Analysis

Gas analysis

Gas analysis has been applied in various places and for various purposes, such as measuring automobile emissions and monitoring flue gas emissions. In recent years, the applications of gas analysis have been expanding even further, with research being conducted into the early detection and diagnosis of diseases through the analysis of breath. Hamamatsu offers a wide range of light sources and detectors for optical gas measurement.

New products for gas measurement

A mid-infrared LED with a peak emission wavelength of 3.3 µm that achieves narrower directivity and higher output power with a reflector. Peak emission wavelengths of 3.9 μm and 4.3 μm are also available.

Back-illuminated InAsSb photovoltaic detector (TO-46 package) with high sensitivity in the spectral band up to 5 μm. We greatly improved the sensitivity temperature coefficient.

Back-illuminated InAsSb photovoltaic detector (ceramic package) with high sensitivity in the spectral band up to 5 μm. We greatly improved the sensitivity temperature coefficient.

Optical gas measurement

Since each gas molecule has its own absorption wavelength, it is possible to measure the concentration of a gas by measuring the absorbance of light at that wavelength. Particularly in the infrared region, there are many absorption wavelengths specific to gas due to the vibration of gas molecules, so the infrared region is used for measuring various gasses.


For example, as shown in the figure, light is irradiated to a gas, and the absorbance is monitored by detecting the transmitted or reflected light. By selecting the optimal device with consideration for the light absorption characteristics of the target gas and its surrounding environment, an optical method can realize faster response, higher accuracy, and longer life than other methods for gas measurement.


High-speed response

The rapid response of optical sensor makes it suitable for real-time gas monitoring. It enables the higher accuracy measurement by integrating and averaging the large number of data even in a short measurement time.

High precision

Optical gas detection is less affected by coexisting gases and water vapor since it detects the specific absorption wavelength of each gas; high selective detection is performed with optical gas measurement.

Long life

Contactless detection with optical measurement contributes to make it robust system and less degradation of sensor itself. Moreover, the frequency of the maintenance can be done less often.

Measurement method and application examples

NDIR (Non-dispersive infrared)

  • Simple detection principle
  • High reliability and superior maintainability
  • High cost performance

Measuring CO2 concentration required for photosynthesis.

Gas leak detection at factories and other work sites.

FTIR (Fourier transform infrared spectroscopy)

  • Wideband spectral information can be obtained
  • Suitable for measuring gases with a wide absorption band
  • Measurement of complex gases is also possible

Concentration analysis of complex gas in automobile exhaust gas.

Analysis of complex gases emitted from factories and the like.

TDLAS (Tunable diode laser absorption spectroscopy)

  • Use of Distributed-feedback (DFB) semiconductor laser
  • High speed and high accuracy measurement is possible
  • Applicable in the field of isotope measurement

Process control with real-time measurement of industrial gas.

Analysis of complex gases emitted from factories and the like.

DOAS (Differential optical absorption spectroscopy)

  • Visible and ultraviolet light also available
  • Optimal for measuring NOx and SOx
  • Less affected by moisture

Real-time monitoring of automobile exhaust gas.

Analysis of pollutant gases in the atmosphere.

Lineup document "Devices for Gas Measurement"

Suitable light sources, detectors, and applications for each optical gas measurement method are introduced.

Absorption wavelengths of gases and compatible products

Absorption wavelengths of various gases such as carbon dioxide (CO2) and methane (CH4), and emission/absorption wavelength ranges of Hamamatsu gas measurement devices are introduced.

Recommended products


  Product image Product name Features NDIR FTIR TDLAS DOAS
Light sources mir LED

Mid infrared LEDs

L1589X series

・Peak emission wavelengths: 3.3 μm, 3.9 μm, 4.3 μm
・Suitable for measuring CO2, CH4
xenon flash

Xenon flash lamps

L13651 series and others

・Instanteneously high peak output
・Low heat generation
・Continuous spectrum

CW Quantum cascade lasers

L1200X series

・MIR semiconductor laser
・Fabricated Distributed-feedback (DFB) structure
・Fast wavelength tuning by current modulation

Xenon lamps

L2273 and others

・High stability
・Continuous spectrum

Deuterium lamps

L2D2 series, S2D2 series

・High stability
・Long life
・Continuous spectrum in UV range
Detectors InAsSb pd

InAsSb photovoltaic detectors

P13243 series

・Supports 5 μm band
・Available with a bandpass filter for CO2, CH4
InAsSb pd

InAsSb photovoltaic detectors

P13894 series

・Supports 8 μm and 10 μm bands
・Non-cooled types and TE-cooled types are available

TypeⅡsuperlattice infrared detector


・Supports 14 μm band
・Liquid nitrogen cooled type
・Excellent linearity
preamp module

Infrared detector modules with preamplifier

C12494 series

・Supports 10 μm band
・High-speed response
・Non-cooled types and TE-cooled types are available

Related documents

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