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Experimental studies of non-radiative relaxation rates in solid state laser materials

Experimental studies of non-radiative relaxation rates in solid state laser materials
Experimental studies of non-radiative relaxation rates in solid state laser materials
Techniques for the measurement of non-radiative decay rates between the optically excited states in solid-state laser materials are described. Two crystals have been investigated, ruby (Cr3+:Al2O3) and Sm2+:CaF2. A review of the spectroscopy of these materials is presented with particular emphasis on aspects relevant to non-radiative decay.

An experiment is described using a second harmonic Nd3+ Nd:glass Q-switched laser to pump ruby crystals. Limiting non-radiative relaxation times were derived from the rise of fluorescence. Rubies varying in concentration between 0.05% and 0.4% were studied over a range of temperatures, 77 -> 7000 K. 4T2 -> 2E(E + 2A), 4T2 -> 2T1 (Eb) and 4T2 -> 2T1 (2A + Ea) non-radiative relaxations were all found to be <4ns in good agreement with the experimental results of other workers.

Two experiments employing a ruby laser to pump Sm2+ :CaF2 are described. The first used a Q-switched laser and, apart from some improvements was similar to the ruby experiment. An upper limit of 4f5 5d pump -> metastable non-radiative decay of 2ns was found for Sm2+:CaF2, The fluorescence decay constant at 295 K was also measured to be 63ns. The second experiment employed a mode-locked laser and the Sm2+:CaF2 non-radiative decay time was <0.5ns.

A new effect - provisionally called 'surface emission' - discovered during the ruby measurements, has been examined in detail and the results of this investigation are presented.

A phase-shift technique for the measurement of non-radiative decay times is examined in detail. A pilot experiment using a self-mode-locked He-Ne laser at 633 nm to pump Sm2+:CaF2 is described. The non-radiative relaxation time found by this method was <33ps.

Suggestions for improved experiments, both pulsed and phase-shifts, are made and the application of the techniques to other materials is discussed.
Anson, Michael
02a55988-68eb-41fa-ba43-1c23fd054861
Anson, Michael
02a55988-68eb-41fa-ba43-1c23fd054861
Smith, R. C.
2890e5a7-d3ae-4850-924a-be58b7a15a73

Anson, Michael (1971) Experimental studies of non-radiative relaxation rates in solid state laser materials. University of Southampton, Electronics and Computer Science, Doctoral Thesis, 151pp.

Record type: Thesis (Doctoral)

Abstract

Techniques for the measurement of non-radiative decay rates between the optically excited states in solid-state laser materials are described. Two crystals have been investigated, ruby (Cr3+:Al2O3) and Sm2+:CaF2. A review of the spectroscopy of these materials is presented with particular emphasis on aspects relevant to non-radiative decay.

An experiment is described using a second harmonic Nd3+ Nd:glass Q-switched laser to pump ruby crystals. Limiting non-radiative relaxation times were derived from the rise of fluorescence. Rubies varying in concentration between 0.05% and 0.4% were studied over a range of temperatures, 77 -> 7000 K. 4T2 -> 2E(E + 2A), 4T2 -> 2T1 (Eb) and 4T2 -> 2T1 (2A + Ea) non-radiative relaxations were all found to be <4ns in good agreement with the experimental results of other workers.

Two experiments employing a ruby laser to pump Sm2+ :CaF2 are described. The first used a Q-switched laser and, apart from some improvements was similar to the ruby experiment. An upper limit of 4f5 5d pump -> metastable non-radiative decay of 2ns was found for Sm2+:CaF2, The fluorescence decay constant at 295 K was also measured to be 63ns. The second experiment employed a mode-locked laser and the Sm2+:CaF2 non-radiative decay time was <0.5ns.

A new effect - provisionally called 'surface emission' - discovered during the ruby measurements, has been examined in detail and the results of this investigation are presented.

A phase-shift technique for the measurement of non-radiative decay times is examined in detail. A pilot experiment using a self-mode-locked He-Ne laser at 633 nm to pump Sm2+:CaF2 is described. The non-radiative relaxation time found by this method was <33ps.

Suggestions for improved experiments, both pulsed and phase-shifts, are made and the application of the techniques to other materials is discussed.

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Published date: 1971
Organisations: University of Southampton, Electronics & Computer Science

Identifiers

Local EPrints ID: 361282
URI: https://eprints.soton.ac.uk/id/eprint/361282
PURE UUID: 3841c96b-cc2e-4823-9f9a-f55f1cd185d7

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Date deposited: 22 Jun 2016 10:46
Last modified: 20 Dec 2018 17:31

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Contributors

Author: Michael Anson
Thesis advisor: R. C. Smith

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