THz Spectroscopy
An emerging application space is the generation of THz emission and THz spectroscopy. IPS has been a pioneer in the generation of semiconductor laser-based THz emission sources for nearly 20 years. Generation of THz radiation is accomplished by combining two single frequency laser sources at slightly different wavelengths inside an optical fiber.
The combined beam is used to illuminate a photo-mixer that generates THz radiation with a wavelength proportional to the frequency difference of the two laser diodes. Using this method, the THz frequency can be swept by precisely changing the temperature of the laser diode sources; see for example US Patents 9,134,054 and 9,806,491.
The frequency sweeping enables numerous absorption spectroscopy applications. Over the frequency range of interest, mode-hop free laser sources with optical isolators are required to enable stable operation.
IPS lasers offers compact single frequency laser sources that are ideal for these applications.
For more information, check out our Literature References.
Related Products
We offer a wide variety of THz spectroscopy lasers, including:
Difference Frequency Generation and Gas Sensing
Difference frequency generation (DFG) is a means of creating a longer wavelength of light by combining two shorter wavelengths within a non-linear crystal. This approach is most commonly utilized for creating a narrow wavelength for gas sensing applications. Typically, this is utilized in the 1.5-4 um wavelength range for common gases such as CO, CO2, CH4, N2O, and H2O.
Frequency stabilized lasers from IPS are utilized for the “fixed” laser source since the laser wavelength is extremely stable and can be precisely specified. This allows the customer to accurately select the “scanning” laser source wavelength to scan the desired DFG wavelength band by temperature tuning in their Difference Frequency Generation and Gas Sensing applications.
Gas sensing applications are generally based on absorption spectroscopy techniques where the DFG wavelength attenuation is measured within a multi-pass gas cell. Accordingly, power and wavelength stability are critical performance characteristics for both the fixed and tunable laser sources for which IPS lasers are ideal.
