Broadband radio-frequency spectrum analysis in spectral-hole-burning media

Abstract

We demonstrate a 20 GHz spectrum analyzer with 1 MHz resolution and >40 dB dynamic range using spectral-hole-burning (SHB) crystals, which are cryogenically cooled crystal hosts lightly doped with rare-earth ions. We modulate a rf signal onto an optical carrier using an electro-optic intensity modulator to produce a signal beam modulated with upper and lower rf sidebands. Illuminating SHB crystals with modulated beams excites only those ions resonant with corresponding modulation frequencies, leaving holes in the crystal's absorption profile that mimic the modulation power spectrum and persist for up to 10 ms. We determine the spectral hole locations by probing the crystal with a chirped laser and detecting the transmitted intensity. The transmitted intensity is a blurred-out copy of the power spectrum of the original illumination as mapped into a time-varying signal. Scaling the time series associated with the transmitted intensity by the instantaneous chirp rate yields the modulated beam's rf power spectrum. The homogeneous linewidth of the rare-earth ions, which can be <100 kHz at cryogenic temperatures, limits the fundamental spectral resolution, while the medium's inhomogeneous linewidth, which can be >20 GHz, determines the spectral bandwidth.

Photon‐echo quantum memory in solid state systems

“…[113]) and fibre optics amplifiers [114,115], but more recently also for laser stabilization to programmable frequency standards [116][117][118][119][120][121][122], and radio frequency analyzers [123][124][125]. These studies, together with extensive fundamental investigations (see [84,126] and contributions by G. Liu and Y. C. Sun in [85]), have resulted in broad understanding of interactions in RE solids.…”

Ultra-wideband spectral analysis using S2 technology

“…Colice et al [14] used perturbation theory to describe this interaction and adapted it to the spectrum analysis application by suitably choosing the input fields. S2 medium was treated as a collection of programmable filters, recording the power spectra of the incident signals that determined the filter shape.…”

“…The spectral coverage demonstrated here was only 3.5 GHz in Tm:YAG, a system that offers 420 GHz bandwidth. Analyses of spectra spanning tens of gigahertz have recently been demonstrated [11,14].…”

“…A systematic study of the dynamic range extension is reported in Ref. [14]. The operation of the device in the compression regime is also discussed in the device and subsystem modeling section later.…”

Broadband analog to digital conversion with spatial-spectral holography

“…Inhomogeneous linewidths range up to 300 GHz in current applicable SSH materials [8,9]. In SSH signal processing experiments, the spectral storage and readout 20 GHz signals has been demonstrated [10].…”