Note: An ultranarrow bandpass filter system for single-photon experiments in quantum optics

Abstract

We describe a combined ultranarrow bandpass filtering setup for single-photon experiments in quantum optics. The filter is particularly suitable for single-photon electromagnetically induced transparency (EIT) experiments, but can also be used in several similar applications. A multipass planar Fabry-Perot etalon together with polarization filters and spatial filtering allows 114 dB pump beam suppression, while the signal beam is attenuated by just 4 dB, although both wavelengths are only separated by 0.025 nm (9.2 GHz). The multipass etalon alone accounts for 46 dB suppression while it has a peak transmission of 65%. We demonstrate EIT experiments in Cs vapor at room temperature with probe power in the femtowatt regime using this filter.

Electromagnetically induced transparency‐based slow and stored light in warm atoms

“…Novikova et al: EIT-based slow and stored light in warm atoms broadening due to imperfect collinear geometry between the control and signal fields. However, application of this technique at the single-photon level for signal pulses only became possible with the development of high-rejection bandpass optical filters based on a multi-pass Fabry-Perot etalon [117]. Such filters provide greater than 110 dB suppression of the unwanted control field without significant attenuation of the signal optical pulse.…”

“…Such stringent requirement of collinearity of the signal and control fields makes spatial filtering inadequate for the necessary separation of the fields at the detection stage. To address this challenge, multiple spectral filtering stages have been required, such as optically pumped filtering cells and/or Fabry-Perot etalons [89,116,117].…”

A mirrorless spinwave resonator

“…Optical resonators are an essential technology for photonic systems. For example, they are used for stabilizing optical frequencies 1 2 3 4 5 , filtering optical fields 6 7 8 , enabling non-linear optics 9 and precision measurement 10 11 12 . There has always been significant interest in developing novel and, in particular, compact optical resonators 13 due to the innumerable applications they enable.…”

A monolithic polarization-independent frequency-filter system for filtering of photon pairs

“…Traditional two-mirror configurations of Fabry-P erot etalons can be difficult to stabilize or set up. [8][9][10][11] We present a filtering setup that relies on cascaded monolithic Fabry-P erot cavities to achieve fully customizable narrow linewidth transmission. Based on the idea of Palittapongarnpim et al, 12 this setup also permits simultaneous filtering of photons at orthogonal polarizations, and extends the free spectral range (FSR) to hundreds of GHz.…”