Yellow picosecond diamond raman laser

Visible pulsed lasers are required for many applications, for example in biomedical imaging [1] and STED microscopy [2]. Such applications often have stringent requirements on the wavelength and pulse duration, which are not directly available from typical solid-state sources. One method of accessing these wavelengths is to use Raman lasers, with diamond being an excellent Raman laser material [3, 4] due to its outstanding thermo-optic properties [5]. Here we demonstrate, to the best of our knowledge, the first monolithic diamond Raman laser, converting pump pulses with duration of 86 ps at 532 nm to 39 ps pulses at 573 nm. With ~400 mW of average pump power, 150 mW of 1st Stokes 573 nm signal was achieved yielding a 37% conversion efficiency. As a Raman gain material, we used a synthetic single-crystal diamond (Element 6). The diamond was 0.5 mm thick and its surfaces were coated to form a monolithic plane-plane Raman laser cavity. The input coupler was highly transparent (HT) for the pump wavelength (532 nm) and highly reflective (HR) for the 1st Stokes (573nm). The output coupling was 82% reflective for 573 nm and HR at 532 nm to double-pass the pump light. Our pump source was a frequencydoubled SESAM Q-switched microchip MOPA producing 86 ps pulses and ~500 mW of average power at 100 kHz repetition rate.