A. J. Cox

Nondiffracting beam from a spatially filtered Fabry-Perot resonator

An experiment was performed in which a single ring from a Fabry–Perot transmission fringe pattern was used to create a nondiffracting beam. The transverse and axial intensity distributions of this beam were measured and found to be in good agreement with previously existing and newly derived theoretical expressions. The diffraction-free range was found from calculation to be proportional to the cavity finesse and length, and the central-spot radius of the beam was theoretically shown to be proportional to the square root of the wavelength and cavity length.

Holographic reproduction of a diffraction-free beam

A high resolution Bessel function profile diffraction-free beam has been reproduced from a holographic optical element made by direct physical interference.

Single mode, piezoelectrically tuned, picosecond short‐cavity dye laser

This letter reports a piezoelectric‐translator‐tuned, short‐cavity picosecond dye laser. This laser, pumped by second or third harmonic picosecond pulses from a mode‐locked Nd+3: glass laser, has been operated at cavity lengths which allow only a single longitudinal mode within the lasing bandwidth of a typical dye gain curve. By varying the cavity length with the piezoelectric translator, the output wavelength has been continuously tuned. With different mirror sets and dyes, the lasing output can be varied across the visible spectrum. The laser output is characterized by a modewidth of 0.3 nm (multimode) and 1.5 nm (single mode). The energy conversion efficiency was found to be roughly 0.3% for single‐mode operation and ≳3% for multimode operation at 600 nm.

Short-cavity picosecond dye laser design

The design of a short-cavity dye laser is described. The laser produces a 2-psec pulse which is tunable in the range between 400 nm and 470 nm when pumped with an 8-psec 355-nm third-harmonic pulse from a modelocked Nd(+3) :glass laser. The laser features a variable calibrated cavity length (10-500 microm), a dye cell through which dye can be continuously flowed, and a compact rugged design. The laser has been incorporated into several picosecond spectroscopy experiments and has proved to be a convenient and useful tunable blue source.

Tunable subnanosecond pulses from short cavity dye laser systems pumped with a nitrogen‐TEA laser

The performance of a laser system consisting of piezoelectrically tunable short cavity dye lasers pumped with a nitrogen‐TEA laser is presented. The design and construction details of the nitrogen laser are given, and its pulse energy and pulse duration under various operating conditions are presented. Typically, UV pulses (337 nm) from the N2 laser had energies of 80 μJ and durations of 600 ps. The shortest dye laser pulses measured were about 90 ps at 600 nm.

Rotational diffusion kinetics of triphenodioxazines in solution

Abstract Experimental determinations of fluorescence kinetics and fluorescence polarization anisotropy kinetics of four triphenodioxazine (TPD) dyes in chloroform obtained following pulsed excitation at 532 nm are presented. The experimental fluorescence depolarization kinetics are compared with rotational diffusion kinetics based on the Debye—Stokes—Einstein hydrodynamic continuum model with stick boundary conditions. Modification of the model for slip boundary conditions is also considered and compared. A CNDO/CI molecular orbital calculation on the parent TPD molecule provides theoretical information on the excited states of these dyes and support for interpretation of the experimental results.

Piezoelectrically tuned short-cavity dye-laser design

A complete design of a short cavity dye laser with a single mode narrow-bandwidth output, and with continuous piezoelectric tuning of this mode is reported. (AIP)

A Tunable Dye Laser In The 400-500 nm Range For Picosecond Spectroscopy

This paper reports recent results in the development of a picosecond short cavity dye laser designed to operate in the 400-500 nm range. The short cavity dye laser is axially pumped with a single Nd+3: glass third harmonic pulse of 11 ps. The output pulse duration, measured with a light gate, is less than 13.8 ps. A theoretical analysis of the laser rate equations is presented which indicates that this blue output pulse may be as short as 1.5 ps and transform limited. single and multiple mode operation are reported with individual mode bandwidths of ≈0.2 nm. Gross tuning of the laser is accomplished by changing dyes and demonstrated for the spectral region of 396 nm to 470 nm. Finer tuning is accomplished by changing the cavity length, while the finest wavelength selection is produced by changing the pumping angle. The maximum energy conversion efficiency measured is ≈6%. This laser should be useful as a broadband source for picosecond spectroscopy of solutions or a nar-rowband source for excitation of gases or low temperature crystals. No practical source of high-power, tunable picosecond pulses in the spectral region of this laser has been previously reported.

Evidence for Nearly Transfom-Limited Pulses from a Short Cavity Blue Dye Laser

We report a short cavity dye laser which generates picosecond pulses shorter than the uv pumping pulse. An extremely short laser cavity length (0–500 μm) and an average mirror reflectivity of 0.6 result in a short photon cavity lifetime, τc. Pulse shortening is predicted by the laser rate equations for photon cavity lifetimes shorter than the pumping pulse [1], [2].

Picosecond Gain Kinetics of 1,4-Bis (2-Methylstyril) Benzene

The production of picosecond pulses in the blue region of the spectrum [1,2] has stimulated our interest in methods of amplifying such pulses. The photophysics and photochemistry of stil-bene laser dyes have not previously been studied by picosecond spectroscopy. We report the gain kinetics and spectra of all trans-1,4-Bis(2-methylstyryl)benzene (Bis-MSB). This laser dye apparently undergoes very little excited-state conversion to a cis-form. Indeed, in related molecules the all trans-form is favored by photoisomerization [3]. Recently, picosecond kinetics of photoisomerization in cis- and trans-stilbene were reported [4]. The gain kinetics reported in this paper are discussed in terms of the excited state conformation, vibrational level, orientation, and population.