Laser Cavity Modes Research Articles

Increased tuning range of Pb<inf>1-x</inf>Sn<inf>x</inf>Se diode lasers using small magnetic fields

A Pb 0.96 Sn 0.04 Se laser diode emitting in the 815-835- cm-1region with current tuning has been examined with applied magnetic fields at 7 kG and below. With increasing magnetic field the laser gain curve broadens, allowing more laser cavity modes (separated by 1.8 cm-1) to oscillate at a given current, and yielding a larger tuning range with current for each cavity mode. Using a combination of current tuning and a constant magnetic field, laser emission was achieved from 800 to 850 cm-1with 90 percent coverage of the spectral interval.

Properties of high-order transverse modes in astigmatic laser cavities*

A theory of the modes in a resonator bounded by the surface of a triaxial ellipsoid was given previously by Weinstein. We have applied this theory to characterize the modes observed in a large-aperture Brewster-window laser. Recognizing that Brewster windows impart astigmatism to the laser cavity, we can find an equivalent ellipsoidal cavity with which to associate the modes. The theory predicts various forms of mode structure, depending on the total astigmatism present. We have verified the theory experimentally and show that high-order modes having rectangular symmetry may be obtained even though a circular aperture is used in the cavity.

Spectral properties of a pulsed dye laser with monochromatic injection

If monochromatic radiation is injected into a pulsed dye laser the output occurs in a few modes of the dye laser cavity around the frequency of injection. The frequency of the injected radiation need not coincide with any of the cavity mode frequencies, provided the initial gain is sufficiently large. The number of oscillating modes in the output is largely determined by the dynamics of the pumping process during the build-up of the laser oscillations. Experimental results and a simple theoretical model are presented.

Resonant Modes in Laser Cavities Immersed in a Homogeneous Moving Medium

Resonant Modes in Laser Cavities Immersed in a Homogeneous Moving Medium

A demonstration of the equality of the phases of laser cavity modes by an oscilloscope trace

The equality of phases of the laser modes can be inferred from an oscillogram of a typical “mode-locked” laser. Therefore, one can use the two photon fluorescent technique to measure the pulse width without measuring the relative contrast ratio.