Speaker
Description
Single-longitudinal-mode (SLM) Raman lasers are emerging as promising light sources that combine very low frequency noise with the potential for watt-level output powers, making them attractive for quantum applications. Previous Raman systems from our group have demonstrated intrinsic linewidths down to the hertz level, with measurements limited by instrument noise. However, such non-monolithic cavity systems can be susceptible to noise from vibrations, air currents, and dust, and can also suffer from mode hopping. Here, we demonstrate the first room-temperature continuous-wave monolithic free-space Raman laser, based on YVO₄. The 1064 nm pump is actively locked to the doubly resonant cavity using the Pound–Drever–Hall technique, generating Stokes emission at 1174 nm. The Raman lasing threshold is 1.7 W, and the laser maintains mode-hop-free SLM operation for more than 7 h. The Stokes intrinsic linewidth is measured to be ∼100 Hz, corresponding to a four-order-of-magnitude reduction in the pump frequency noise. The monolithic cavity is largely insensitive to vibrational noise and air currents, and is therefore a key step towards developing Raman lasers with hertz-level integrated linewidths. Numerical modelling suggests that, by optimising the pump cavity, scaling to higher pump powers, and using a sub-MHz-linewidth pump laser, this platform could enable sub-Hz intrinsic linewidths and low relative-intensity-noise and frequency-noise levels suitable for quantum gate operations, while supporting watt-level output powers. Furthermore, a reduction in the integrated linewidth from ~6 MHz to ~160 kHz is observed.
| I am the presenting author | Yes |
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