Far Infrared / Terahertz Gas Lasers | Edinburgh Instruments

Far Infrared / Terahertz Gas Lasers

With over 30 years expertise in designing and manufacturing a range of optically pumped FIR (Terahertz) lasers, our products are used in applications where coherent radiation in the range of 40 μm to 1.22 mm (0.25 –7.5 THz) is required. When combined with our PL Series of CO2 lasers the FIR laser becomes a powerful tool for taking laser line measurement at high peak powers.A range of optically pumped, far infrared (FIR) lasers are available for applications that require coherent radiation in the spectral range of 40 µm to 1.22 mm, the TeraHertz (0.25 – 7.5 THz) frequency range.

FIR laser frequencies arise from rotational transitions in an excited vibrational state of a polar gas molecule at low pressure. The optically pumped FIR laser relies on the selective absorption of tunable infrared radiation to create the population inversion between rotational states and hence generate laser action. In practice, a small number of molecules are chosen to provide discrete frequencies across the entire FIR spectrum from 40μm upwards.

Output powers of 150 mW and 500 mW at the 118.8 μm and 184.3 μm methanol (CH3OH) lines can be guaranteed depending on the model of the Edinburgh Instruments CO2 pump laser used.
The FIR lasers are Invar bar stabilised and are available with either single or dual output. The products range from the FIR 295, FIR 395 (Twin FIR output), to the FIRL 100.

Power Supplies

Conventional high voltage DC excitation is used to excite the laser discharge. Each laser is driven by one of the LPS family of new, compact (19″” rack mounted) switch mode power supplies. These supplies are based on resonant inverter technology for the highest efficiencies and reliability. Designed for stable output current operation, the jitter of the PL lasers with the LPS range has been measured at typically 200kHz/sec and can achieve below 60kHz in the case of the PL3. The PL6 or a PL5 laser can be used to pump a 295 or 395
Continuous Wave (CW) or chopped operation up to 1kHz is available with the LPS range. The PL5 laser can be optionally driven with the versatile PS4P valve controlled power supply providing programmable CW, chopped and pulsed operation. In pulsed mode the laser peak output power is typically five times the CW level at repetition rates up to 1 kHz and with pulse widths down to 100 microseconds.


A full range of accessories and options, such as coolers, gas handling systems, stabilisers, are available for each laser.