Raman fiber laser with a wavelength of 1.48 μm for ultrafast heating of cryopreserved microobjects

A millisecond cascaded Raman phosphosilicate fiber laser emitting 1475-nm pulses with an energy of 8.5 mJ is demonstrated. The laser is designed for ultrafast laser heating of vitrified microscopic samples with a linear size of ∼100 μm, including preimplantation embryos. The laser is pumped by an ytterbium-doped fiber laser operating in a repetitively pulsed regime, which is set by modulating the current of laser diodes. The spectral power and temporal characteristics of the radiation are considered. The maximum power of Raman lasing at P₂O₅ centers is limited by the competing process of scattering at SiO₂ centers in the phosphosilicate fiber.