Multi-Gigahertz radar range processing of baseband and RF carrier modulated signals in Tm:YAG

We report the energy level structure of the 3 H6 and 3 H4 multiplets for Tm 3+ doped congruent LiNbO3, as well as the decoherence properties and their temperature dependencies for the 3 H6(1) ↔ 3 H4(1a) transition at 794 nm. It is shown that this material provides very significant improvements in bandwidth, time-bandwidth product, and sensitivity for spatial-spectral holographic signal processing devices and quantum memories based on spectral hole burning. The available signal processing bandwidth for 0.1% Tm 3+ :LiNbO3 is 300 GHz versus 20 GHz for Tm 3+ YAG. The peak absorption coefficient for 0.1% Tm 3+ :LiNbO3 is 15 cm −1 at 794.5 nm compared with 1.7 cm −1 for 0.1% Tm:YAG at 793 nm, and the total absorption strength is eighty times stronger. The oscillator strength for Tm 3+ :LiNbO3 is about twenty five times larger than that for Tm 3+ :YAG, making the material five times more sensitive for processing high-bandwidth analog signals. The homogeneous linewidth, which determines processing time or spectrum analyzer resolution, is 30 kHz at 1.6 K and 350 kHz at 6 K, as measured by photon echoes. Those values establish potential time-bandwidth products of 10 7 and 7 ×10 5 respectively. The temperature dependence of the homogeneous linewidth was explained by observation of a 7.8 cm −1 crystal field level in the ground multiplet and direct phonon coupling. The excited state 3 H4 lifetime T1 is 152 µs and the bottleneck lifetime of the lowest 3 F4 level is 7 ms from photon echo measurements. These factors combine to provide a surprisingly large increase in key parameters that determine material performance for spatial-spectral holography, quantum information, and other spectral hole burning applications.

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“…In combination, these measurements provided insight into the multiple Tm 3+ sites and disorder of the congruent LiNbO 3 .…”

mentioning

confidence: 95%

Optical decoherence and energy level structure of 0.1%Tm3+:LiNbO3

2012

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“…The applications include frequencydomain data storage, 2 time-domain data storage, 3,4 spectralspatial correlation, 5 temporal pattern recognition, 6 optical data processing, 7,8 radio-frequency spectrum analysis, 9 and the use of spectral holes as frequency references. 10,11 Rare-earth ions doped into crystalline hosts are particularly suited for study using nonlinear spectroscopic methods such as hole burning, 12 and for use in spectral hole-burning applications.…”

Section: Introductionmentioning

confidence: 99%

Hole-burning techniques for isolation and study of individual hyperfine transitions in inhomogeneously broadened solids demonstrated inPr3+:Y2
Nilsson¹,
Rippe²,
Kröll³
et al. 2004
Phys. Rev. B
193
6
83
0
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Due to their narrow homogeneous linewidths, rare-earth ions in inorganic crystals at low temperatures have recently been given considerable attention as test materials for experiments in coherent quantum optics. Because these narrow linewidth transitions have been buried in a wide inhomogeneous line, the scope of experiments that could be carried out in these materials has been limited. However, here we present spectroscopic techniques, based on spectral hole burning and optical pumping, which allow hyperfine transitions that are initially buried within an inhomogeneously broadened absorption line to be studied with no background absorption from other transitions. A sequence of hole-burning pulses is used to isolate selected transitions between hyperfine levels, which makes it possible to directly study properties of the transitions, e.g., transition strengths, and gives access to information that is difficult to obtain in standard hole-burning spectroscopy, such as the ordering of hyperfine levels. The techniques introduced are applicable to absorbers in a solid with long-lived sublevels in the ground state and where the homogeneous linewidth and sublevel separations are smaller than the inhomogeneous broadening of the optical transition. In particular, this includes rare-earth ions doped into inorganic crystals and in the present work the techniques are demonstrated in spectroscopy of Pr

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“…Measurements in Tm:YAG [26] indicated that even under extreme conditions of operation such as high optical or RF power and wide frequency span, 200 kHz spectral resolution was still achievable. The other key requirement for several spectral surveillance applications is ultra-wide bandwidth processing capability.…”

Section: Materials Module: Novel S2 Materials Developmentmentioning

confidence: 99%