The Thorlabs Long-Wave Infrared Supercontinuum Laser (LWIRSC) expands Thorlabs' supercontinuum offerings into the long-wave infrared, accessing the molecular fingerprint region. This laser complements our award-winning mid-infrared supercontinuum laser (Item # SC4500, 1.3 μm to 4.5 μm) by extending the wavelength range to cover approximately 3.5 μm to 11 μm (2850 cm-1 to 910 cm-1) with >20 mW of average output power in a single-mode, achromatically collimated beam.

• Linearly Polarized, Single-Mode, Collimated Output Beam
• >20 mW Output Power
• Purgeable Enclosure
• Spatial profile of the LWIRSC laser full emission band at 1 meter, measured in mm.

This spectral coverage overlaps with a significant portion of the molecular fingerprint region (5 - 15 μm) and enables absorption spectroscopy of molecular vibrations in everything from trace gases to liquids and solid samples. The brightness of the LWIRSC laser exceeds traditional incoherent sources such as Globars and synchrotrons by orders of magnitude.

The typical power spectral density as a function of wavelength is provided here. Please note that this is a sample spectrum and that small variations may occur from unit to unit. Also note that the spectrum is subject to environmental conditions. We provide two sets of data to illustrate this point. The "purged" data was measured with the OSA207C Optical Spectrum Analyzer, LWIRSC, and most of the beam path in clean dry air (CDA). The "unpurged" data was taken in a typical laboratory environment. Note that the feature at 4.2 μm is due to CO2 absorption, and the fine structure from 5 - 7 μm is due to H2O absorption.

Features

• >20 mW Output Power Over 3.5 - 11 µm Range
• Femtosecond Pump Architecture Minimizes Shot-to-Shot Noise
• Based on Intra-Pulse Difference Frequency Generation with No Moving Parts
• High Brightness Single-Mode Achromatically Collimated Output Beam
• Compatible with Fourier-Transform Infrared (FTIR) Spectrometers
• Available with Water Cooling for Vibrationally Sensitive Applications (Contact This email address is being protected from spambots. You need JavaScript enabled to view it.)

The LWIRSC architecture is based on the all-fiber femtosecond mid-infrared laser technology developed for our SC4500 laser, followed by intra-pulse difference frequency generation in a nonlinear crystal.a,b This patented technology (US Patent 11,815,782) offers a compact and robust platform which, unlike conventional difference frequency generation sources, does not rely on temporal alignment of optical pulses. As a result, the laser does not include any variable delay lines or moving parts, reducing the cost and complexity of the laser. The repetition rate of 50 MHz makes it compatible with commercially available FTIR spectrometers. It is recommended to use uncoated gold mirrors with the LWIRSC laser. The high-quality single-mode output beam is amenable to fiber coupling; contact This email address is being protected from spambots. You need JavaScript enabled to view it. to discuss how this source could be configured. 

The high brightness well into the mid-infrared make the LWIRSC laser an ideal source for sensing and spectroscopy applications. These range from environmental sensing of greenhouse gases to standoff detection in the field to spectroscopy in the lab using standard FTIR spectrometers. In addition, this laser can be used as a source of femtosecond pulses in the mid-infrared by filtering the output through a bandpass filter.

5. Salem, S. Backus, D. Liu, C. Wan, S. Domingue, M. Kirchner, A. Cable, and P. Fendel,"5-11 μm Supercontinuum Generation Using Cascaded Nonlinearities in Fluoride Fiber and ZGP,"in Conference on Lasers and Electro-Optics, OSA Technical Digest (Optica Publishing Group, 2021), paper STh1L.5.
6. Timmers, A. Kowligy, A. Lind, F. C. Cruz, N. Nader, M. Silfies, G. Ycas, T. K. Allison, P. G. Schunemann, S. B. Papp, and S. A. Diddams, "Molecular fingerprinting with bright, broadband infrared frequency combs,"Optica 5, 727-732 (2018)

Applications

• Absorption Spectroscopy in the Molecular Fingerprint Region
• Environmental Sensing
• Standoff Detection of Chemical and Biological Threats
• Infrared Spectromicroscopy
• Ultrafast Spectroscopy
• Femtosecond Pulse Generation in the Mid-Infrared
• Optical Coherence Tomography
• Semiconductor Inspection