This communication describes a new method for producing stable, high concentrations of Sc 2+ in optically clear CaF 2 crystals. We have achieved Sc 2+ concentrations as high as 3 × 10 18 cm −3 without degradation of optical quality. We have converted as much as 5% of the scandium dopant to the divalent state. The concentration of divalent scandium is stable during room temperature storage for periods of at least one year.

HE RAPIDLY developing field of biophotonics integrates the descriptive and analytical aspects of the life sciences and photonics to register unprecedented achievements in the detection, imaging, identification, kinetics, and manipulation of biological materials. Biophotonics is used in biology to probe formolecular mechanisms,function,andstructure.Inmedicine, biophotonics is used to study tissue and blood at the macroand micro-organism level to detect, diagnose, and treat diseases in ways that are noninvasive or minimally invasive to the body. Applications of biophotonics include using light to image or selectively treat tumors, sequence DNA, and identify single biomolecules within cells. Against this backdrop of science and technology, this issue of the IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS (JSTQE) on Biophotonics features articles covering a range of disciplines that describe advances and revolutionary developments in the field. Manuscripts on the latest research and developments in photonics-driven areas such as: bioimaging, biosensors/assays, contrast agents, multicolor probes, biomolecular mechanisms and function, biomolecular structure, advanced medical devices, biocomputers, optical limiters, and biophotonic and biocompatible materials were solicitedforthisJSTQEissue.ThepaperspublishedinthisJSTQE volumerepresenttheimpactofbiophotonicsonnewunderstanding of fundamental biological processes, innovative approaches to major health issues such as novel methods for medical diagnosis and treatment, and new techniques and technologies to satisfy biorelated national security needs such as the detection of toxic agents and pathogens, and associated countermeasures. This issue’s title changed from the prior “Lasers in Medicine and Biology” to the forward-looking “Biophotonics” and is deemed necessary to more properly characterize the rapid and numerous developments that are taking place at the intersection of the life sciences and photonics. The new name subsumes the previous topical areas of the old designation.

Continuous-wave laser emission at 3.41 μm from an erbium-doped LiYF4 crystal (Er:YLF) at 77 K is reported. Operation of this 4 - level laser is based on the Er3+ 4F9/2 - 4I9/2 transition. An output power of 12 mW and a slope efficiency of 2% have been achieved.

This communication describes a new method for producing stable, high concentrations of Sc2+ in optically clear CaF2 crystals. We have achieved Sc2+ concentrations as high as 3 × 1018 cm−3 without degradation of optical quality. We have converted as much as 5% of the scandium dopant to the divalent state. The concentration of divalent scandium is stable during room temperature storage for periods of at least one year.

We obtained coherent radiation in the spectral region between 223 and 243 nm by frequency mixing the tunable output of a solid-state Ce(3+):LiCAF laser with 1.064-mum radiation from a Nd(3+):YAG pump laser in a beta-barium borate nonlinear crystal.

A polymeric high gain scattering medium based on IR-26 laser dye mixed with sub-micron alumina scatterers is described. Optical pumping at 1.06 micrometer with a Q-switched Nd:YAG laser results in isotropic, narrowband emission peaking at 1.18 micrometer. Alternative high gain, narrowband visible stimulated emitters utilizing a high density of microprism retroreflectors for optical feedback are also described. Optical pumping at 532 nm with the Q-switched output of a frequency-doubled Nd:YAG laser results in narrow linewidth, Stokes-shifted laser emission near 600 nm.

The performance of a flash-lamp-pumped Cr:LiSAF unstable laser resonator utilizing a fourth-order super-Gaussian variable reflectivity mirror as an output coupler is described. The super-Gaussian mirror results in a smooth, flattop transverse beam profile in the near field that is advantageous for nonlinear frequency-conversion applications. Long-pulse and Q-switched operation of the Cr:LiSAF unstable laser resonator are described and compared with stable resonator operation. We obtained tunable ultraviolet radiation extending from 267 to 290 nm by frequency mixing theQ-switched Cr:LiSAF laser output with lithium triborate and beta-barium borate nonlinear crystals.

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text J. F. Pinto and L. Esterowitz, "Distributed-Feedback Laser Action in Ce3+-doped Colquiriites," in Advanced Solid State Lasers, C. Pollock and W. Bosenberg, eds., Vol. 10 of OSA Trends in Optics and Photonics Series (Optica Publishing Group, 1997), paper US8. Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

Summary form only given. The cerium-doped colquiriite lasers, Ce 3+:LiCaAlF6 (LiCAF) and Ce3+:LiSrAlF 6 (LiSAF), have emerged as convenient, compact sources of tunable ultraviolet (uv) radiation. The notable features of these solid-state, vibronic laser systems include single-knob tuning, relative ease of use, and the capacity for being optically pumped with the frequency quadrupled output of a commercial Nd3+ laser

Distributed-feedback (dfb) laser oscillation is reported in Ce3+-doped LiSrAlF6 (LiSAF). Tunable operation of the Ce3+:LiSAF dfb laser is achieved in the ultraviolet wavelength region from 289 to 293 nm. At the peak emission wavelength of 290 nm, dfb lasing linewidths are less than the 1 Å resolution limit of the 1 m spectrometer.

Radiation in the spectral region between 223 - 243 nm is obtained by frequency mixing the tunable output of a solid-state Ce3+:LiCAF laser with residual 1.064 μm radiation from the Nd3+:YAG pump laser in a BBO nonlinear crystal.

Wideband UV-visible luminescence under laser or CW lamp excitation was observed in y-irradiated Sc and Sc-Ce doped CaF2 crystals: 1) at 380 nm in Sc:CaF2 and Sc:Ce:CaF2 crystals, attributed to Sc2+ ions and 2) at 300 nm in Sc,Ce:CaF2 crystals, due to Sc-Ce aggregate centers.

Stokes and anti-Stokes UV-visible luminescence was investigated in γ-irradiated Sc and Sc-Ce doped CaF2 crystals. Wideband Stokes luminescence under laser or CW lamp excitation was measured: (1) at 380 nm (luminescence decay time τ ~ 17 μs) in Sc: CaF2 and Sc,Ce: CaF2 crystals, attributed to Sc2+ ions and (2) at 300 nm (τ ~ 40 ns) in Sc,Ce: CaF2 crystals, due to Sc-Ce aggregate centers. Anti-Stokes luminescence in the 250–350 nm spectral range with a 1 μs lifetime can be explained by exciton luminescence.

Mirrorless, distributed-feedback (DFB) laser action has previously been demonstrated in high gain media such as dyes and color center lasers. The feedback mechanism, which is associated with spatial modulation of the gain and refractive index, results in narrow linewidth oscillation within the DFB laser structure. In this paper, we describe DFB laser action in Ce:doped LiCAF and LiSAF gain media for the first time. Laser action for both hosts occurs near 290 nm.

Laser emission from Tm:YALO is observed over the range 1.93-2.00 mu m. A model including reabsorption loss and polarization effects, predicting the output wavelength as a function of laser parameters, is used to design a Tm:YALO laser with output restricted to 1.94 mu m, without employing a tuning element. This laser is potentially useful for medical applications, owing to the strong absorption coefficient at 1.94 mu m in liquid water (twice that of the 2.02-mu m Tm:YAG laser and four times that of the 2.09-mu m Ho:YAG laser).

A Tm:YALO laser end-pumped by a 794-nm laser diode array is reported. The output power is 1.2 watts when the quasi-cw diode array is operated at a 50 Hz repetition rate (5% duty cycle). The Tm:YALO laser operates at 1.94μm with an output coupling of 2.5%, and at 1.945μm and 1.99μm simultaneously with an output coupling of 2.0%. The dependence of laser wavelength on output coupling is consistent with a previously reported Tm:YALO laser pumped by a Ti:sapphire laser

Improved gain-switched laser operation of cerium-doped LiCaAlF6 (Ce3+:LiCAF) and LiSrAlF6 (Ce3+:LiSAF) crystals is described. Pumping with the quadrupled Nd:YAG laser at 266nm, the Ce3+:LiCAF laser delivers an output energy of 10.2 mJ at an operating wavelength of 288 nm, with a corresponding slope efficiency of 28%, and tunability from 281 to 315nm. For the Ce3+:LiSAF laser, an energy of 5.4 mJ at 290nm, slope efficiency of 16%, and tuning range extending from 283 - 313 nm are obtained.