785 nm Laser Module

Where 785 nm lasers are used

785 nm is the single most specified excitation wavelength in analytical instruments, because it sits at the point where fluorescence is suppressed enough for real samples while silicon detection still works. Everything longer costs you detector sensitivity, everything shorter costs you background.

• Raman spectroscopy. The de facto standard for organic chemistry, pharmaceutical analysis, forensics and biological tissue.
• Raw material identification. Handheld and at-line Raman units for incoming goods inspection in pharmaceuticals and chemicals.
• Food and material sorting. Near infrared response of organic matter at line speed.
• Confocal and deep tissue imaging. Less scattering in tissue than visible excitation.
• Laser diffraction particle analysis. Established wavelength with well characterised scattering behaviour.

One limit worth knowing before you specify it: at 785 nm excitation, a Raman shift of 3000 cm⁻¹ lands near 1020 nm, which is close to the edge of useful silicon sensitivity. If your bands of interest sit that high, check your detector before you check your laser.

785 nm or a neighbouring wavelength?

785 nm is the safe default when you do not yet know the full range of samples an instrument will see. Move to the 1064 nm laser only when 785 nm still shows a rising fluorescent background, and accept roughly a third of the signal in exchange.

Move the other way, to the 660 nm laser module or the 532 nm laser module, when your samples are known to be clean and you want the signal back.

For high resolution work, the linewidth of the source matters as much as its wavelength. See our narrow linewidth lasers for the stabilized versions.