Coherent has launched the Genesis 355 lasers, a range of solid state lasers providing true CW output in the ultraviolet (355nm). Based on the company's optically pumped semiconductor laser (OPSL) technology, Genesis 355 products are available with output powers of 40, 60, 80 and 100mW. As with other OPSLs, the lasers feature excellent beam quality (M²<1.2) and low noise (<0.5 per cent rms). They have shown high performance and reliability in beta testing in target bio-instrumentation UV applications, such as flow cytometry and confocal microscopy.
Typically, applications for CW ultraviolet lasers have had to use either legacy gas laser technology or mode-locked solid state laser technology offering only pseudo-CW performance. These mode-locked lasers generate peak powers at the kilowatt level and beyond, which can cause severe limitations in biological applications.
The CW, low-noise output of Genesis 355 is ideal for flow cytometry applications such as egg and fertilised-egg sorting, where the peak power of alternative mode-locked lasers poses significant risk of mutagenic damage to the DNA in the sorted cells. The lasers are also well-suited to emerging confocal microscopy applications where their short wavelength and low M² beam are needed for optimum excitation of Hoechst and Indo dyes. These confocal microscopes often rely on fibre delivery, which can be problematic with high peak power lasers.