Tunable Cr Research Articles

Sensing lesions in tissues with light

The use of light for probing and imaging of biomedical media offers the promise for development of safe, noninvasive, and inexpensive clinical imaging modalities with diagnostic ability. Various properties of light together with the ways it interacts with biological tissues may provide multiple windows to peer inside body organs. Principles and methods for extraction of information about body functions and lesions that capitalize on temporal, spectral, polarization, and spatial characteristics of transmitted light are briefly outlined. As illustrations of the potential and efficacy of light-based techniques, time-sliced and spectroscopic images of normal and cancerous human breast tissues recorded with a femtosecond Ti:sapphire laser and a broadly tunable Cr:forsterite laser, respectively, are presented.

Continuous-wave broadly tunable Cr^2+:ZnSe laser

We report room-temperature operation of an all-solid-state broadly tunable continuous-wave Cr(2+):ZnSe laser. Output power of 250 mW, an absorbed power slope efficiency of 63%, and continuous tunability from 2138 to 2760 nm are demonstrated.

Self-starting passively mode-locked tunable Cr4+: yttrium–aluminum–garnet laser with a single prism for dispersion compensation

A self-starting passive mode-locked Cr4+:yttrium–aluminum–garnet laser that uses a saturable Bragg reflector with a single prism for dispersion compensation instead of the standard prism pair is demonstrated. We observed over 230 mW average output power with a pulse width of 400 fs at center wavelengths shorter than 1.5 μm. The tuning range for cw laser operation extends from 1345 to 1557 nm. The mode-locked pulses are self-starting and tunable from 1420 to 1510 nm by means of lossless prism tuning without aperture.

Mid-infrared DF laser pumped by a tunable and narrow-line Cr^4+: forsterite laser

We describe results of experiments on optically pumped HF and DF overtone transitions that use a specially developed tunable and narrow-line Cr4+: forsterite laser. The performance of this Cr4+:forsterite laser is first reported. Cascading laser transitions were generated in DF(3–2) and DF(2–1) bands between 3.64 and 3.85 µm. The experimental results are compared with the theoretical predictions of a computer model.

Compact tunable Cr:LiSAF laser for infrared matrix-assisted laser desorption/ionization.

A tunable Cr:LiSAF laser-pumped optical parametric oscillator was used for mid-infrared matrix-assisted laser desorption/ionization (MALDI) mass spectrometry experiments. The mass spectra of substance P, bovine insulin and pd(T)10 in the 2.88-2.96 microns range showed excellent single shot signal quality (signal-to-noise-ratio, resolution) but poor shot-to-shot reproducibility. The reproducibility is expected to improve with more stable laser design. No correlation was found between the absorption spectrum of the matrix and the MALDI response.

Diode-pumped, continuous-wave, single-mode, tunable Cr^3+:LiSrAlF_6 ring laser

We describe an all-solid-state, tunable, single-frequency, continuous-wave Cr(3+):LiSrAlF(6) ring laser. When pumped with 360 mW of power from a single laser diode the laser has tuning range from 814 to 892 nm and a free-running frequency stability relative to a reference cavity of 60 kHz rms. Further stabilization promises to be possible by use of standard servo electronics. We demonstrate the use of the laser by performing Dopplerfree saturation spectroscopy of the cesium D2 line.

Frequency tripling of a Q-switched Cr:LiSAF laser to the UV region

Frequency tripling of a Q-switched, tunable Cr:LiSAF laser to the UV wavelength region is accomplished by a mixing scheme involving second harmonic generation in lithium triborate (LBO), followed by sum frequency generation in /spl beta/-barium borate (BBO). The generated UV output is tunable between 260 nm and 320 nm.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>