Mid Infra-Red Generation

The Sirah mid-infra-red generation unit (MIR) is designed to generate powerful laser pulses in the wavelength range from 4.8 to 11 µm. It is operated with a Nd:YAG pump laser, a PrecisionScan dye laser, equipped with either a single or a double grating resonator with 1800 lines / mm gratings, and an optical para­metrical amplifier unit (OPANIR).


A frequency doubled, injection seeded Nd:YAG laser  is used to pump a PrecisionScan dye laser, operated in the red spectral range. The dye laser output and a fraction of the residual 1064 nm pulse from the Nd:YAG laser are mixed in a LiNbO3 crystal for difference frequency generation. The generated IR pulse passes a second LiNbO3 crystal, pumped by the remaining 1064 nm pulse, and tuned to act as an optical parametrical amplifier. The OPA amplifies the initial IR pulse and generates signal and idler frequency. The difference frequency of these two pulses is generated in a AgGaSe2 crystal. Due to injection seeding, the resulting linewidth is determined by the configuration of the dye laser oscillator.

Optical Layout


Tuning Range


MIR tuning curves, when pumping with approximately 550 mJ @ 532 nm

Energy Output

Pump Laser Dye Laser Output Energy
MIR energy output at 7.5 µm (maximum Styryl 8 in Ethanol). See tuning curves for output energies at other wavelengths.
550 mJ @ 532 nm PrecisionScan-G-18 100 µJ
550 mJ @ 532 nm PrecisionScan-D-18 90 µJ
430 mJ @ 532 nm PrecisionScan-G-18 70 µJ
430 mJ @ 532 nm PrecisionScan-D-18 63 µJ

General Characteristics

Required Equipment Injection seeded Nd:YAG laser
Sirah PrecisionScan dye laser
Sirah OPANIR near-infra-red unit
Maximum Pump Energy 550 mJ 532 nm,
Dye Laser Resonator 1800 lines / gratings recommended
1800 lines / double grating resonator possible
Dye Laser Amplifier Enhanced Beam Profile Cell recommended
Repetition Rate 10 Hz repetition rate recommended
Crystal Tuning Mode Look-Up Table
IR Beam Polarization Horizontal, > 98%
IR Beam Diameter (typical) 5 – 9 mm, depending on laser configuration
IR Beam Divergence < 0.5 mrad
IR Linewidth < 1.5 x Dye Laser Linewidth
Tuning Range DFM-8M 4.8 .. 8.0 µm (standard)



All Dimensions in mm. Specifications are subject to change without notice.

Literature & Downloads

Datasheet Mid Infra-Red Generation