Tunable spectral squeezers based on monolithically integrated diamond Raman resonators

We report on the generation and tuning of single-frequency laser light in a monolithic Fabry-Perot diamond Raman resonator operating in the visible spectral range. The device was capable of squeezing the linewidth of a broad multi-mode nanosecond pump laser ( & UDelta; nu p = 7.2 & PLUSMN; 0.9 GHz at lambda p = 450 nm) to a nearly Fourier-limited single axial mode Stokes pulse ( & UDelta; nu S = 114 & PLUSMN; 20 MHz at lambda S = 479 nm). The tuning was achieved by precise adjustment of the resonator temperature, with a measured frequency-temperature tuning slope of partial differential nu 0 / partial differential T & AP; -3 GHz/K, and a temperature dependence of the first-order Raman phonon line of partial differential nu R / partial differential T & AP; +0.23 GHz/K. The Stokes center frequency was tuned continuously for over 20 GHz (more than twice the free spectral range of the resonator), which, in combination with the broad Ti:Sapphire laser spectral tunability, enables the production of Fourier-limited pulses in the 400-500 nm spectral range. The Stokes center-frequency fluctuations were 52 MHz (RMS) when the temperature of the resonator was actively stabilized. Moreover, the conversion efficiency was up to 30%, yielding an overall power spectral density enhancement of > 25 x from pump to Stokes pulse.

Automated summary

This study reports on the generation and tuning of single-frequency laser light in a monolithic Fabry-Perot diamond Raman resonator in the visible spectral range. The linewidth of a multi-mode nanosecond pump laser was squeezed to a nearly Fourier-limited single axial mode Stokes pulse by adjusting the resonator temperature. The tuning range was over 20 GHz, enabling the production of Fourier-limited pulses in the 400-500 nm spectral range.