A tunable waveguide CO2 laser using Fabry-Perot modulator and fox-smith type mode selector

A tunable waveguide CO₂ laser was constructed and tested. Efficient output was obtained over expanded tuning range making use of the coupling modulation through the F-P modulator. A fox-smith type mode selector was used to obtain the tuning range wider than the longitudinal mode spacing.A continuous tuning range of 2.2GHz was experimentally obtained.     

A simple microcomputer- controlled CO2 laser wavelength tuning system

A CO₂ laser wavelength tuning system with microcomputer-controlled diffraction grating positioning is reported. The system employs a dc micromotor operating in a closed loop positioning servo and is characterized by simplicity of hardware. Fast wavelength tuning over a broad spectral range is achieved with the variable positioning speed technique. System performance is evaluated in conjunction with a TEA CO₂ laser.     

Side-wall emitting ZnSe/AlN waveguide CO2 laser

A side-wall emitting ZnSe/AlN waveguide CO₂ laser, which is able to extract the output power from the waveguide wall, is proposed. In the proposed scheme, four polished AlN plates are cemented to form a 16 cm long waveguide with 1.9×1.9 mm² cross section. One of the AlN plates is partially replaced by the ZnSe plate. This part is used as an output window. To confirm the workability of the proposed scheme, a trial laser was constructed and tested. The output power of several milliwatts was observed from the ZnSe waveguide wall.     

Optically pumped NH3 laser using a continuously tunable CO2 laser

The use of a continuously tunable CO₂ laser to optically pump the NH₃ laser via previously inaccessible absorption lines is described. Efficient laser action has thus been achieved in the 11–13 μm region on transitions formerly only obtained in buffered mixtures.     

Saturated absorption of C2H4 with a CO2 waveguide laser

Saturated spectroscopy of C₂H₄ was performed with a CO₂ waveguide laser. Seventeen lines were measured with a precision of the order of 200 kHz. On the basis of these data and of a new highly accurate determination of the ground-state rotational constants a better analysis of the ν₄, ν₇, and ν₁₀ levels was achieved.     

Mathematical modelling of gain-switched RF-excited CO2 waveguide laser

The detailed mathematical models for the evolution of light pulses in RF-excited CO2 waveguide lasers are derived. Explicit expressions for the pulse characteristics in RF-excited CO2 waveguide lasers are obtained. The effects of losses and unsaturated gain on output power are calculated.     

New CH2F2 FIR laser lines pumped by a tunable WG CO2 laser

8 new large offset FIR laser lines of CH₂F₂ have been discovered by pumping with a high tunability waveguide CW CO₂ laser. Optoacoustic measurements of CH₂F₂ have also been performed and the pump offsets of the new and of previously known lines have been measured and checked. Some assignments are proposed and a few assignments found in literature are checked     

Phase-locking of the tunable two-dimensional axisymmetrical folded-combined CO2 laser

The frequency modulation of the two-dimensional (2D) axisymmetrical folded and combined (ASFC) CO₂ laser is performed by a blazed grating. Its principle of phase-locking is studied in detail. The properties of the injected mode in ASFC and the mode coupling coefficient, which are analyzed, will be considered to be the main factors of the phase-locking. It is shown that the effect of phase-locking will not be influenced when the blazed grating is adjusted. However, it will influence the distribution of the light intensity to some degree.     

Infrared spectroscopy of OCS,SO2, O3 with a CO2 waveguide laser

Infrared spectroscopy of OCS, SO₂, and O₃ has been performed with a CO₂ waveguide laser. The spectra observed were analyzed with data available and assignments are proposed.     

A 3 kW average power tunable TEA CO2 laser

A high average power line-tunable TEA CO₂ laser is described. Average output power up to 3 kW is achieved at repetition rate of 180 Hz. The maximum output power is almost equal among the four spectrum bands of CO₂ laser (the P and R branches of 00°1–10°0 and 00°1–02°0 transition bands). Several special technologies including rotating spark gap switching, PCB (printed circuit board) preionization and zeroth-order grating coupling are employed.     

High precision spectroscopy of SF6 with cw high pressure tunable CO2 laser

Investigations are reported on the frequency characteristics of the cw high pressure CO₂ laser and its use for high precision spectroscopy. The problem of using a cw tunable CO₂ laser with a mixture of a few isotopes (¹²C¹⁶O₂, ¹²C¹⁸O₂, ¹²C¹⁶O¹⁸O and others) in a cw high pressure tunable CO₂ laser is discussed. Broadening of the tuning range has given us the opportunity to find seven new absorption lines of SF₆ near the transition P(20) of the 00⁰1–10⁰0 band of the CO₂ laser.     

An efficient,RF excited,waveguide CO2 laser

A CW waveguide CO₂ laser excited by a transverse radiofrequency discharge is described. An efficiency of 8.5% (laser power/RF power from supply) has been achieved and an output power of up to 4.6 W.     

Tunable electrooptically Q-switched RF excited CO2 waveguide laser with two channels

A tunable electrooptically Q-switched RF excited waveguide CO₂ laser with two channels is presented. Q-switched pulses have been obtained from one of the channels. The peak power is 300 W and the pulse width is 140 ns. CW laser output has been obtained from the other channel, which can been tuned by a PZT. The short-term heterodyne stability can be up to 10⁻⁹.     

A waveguide CO2 laser operating in a Gaussian mode: Experimental analysis

An experimental analysis of the dielectric waveguide laser modes has been carried out and it has been shown that the maximum power output is related to the EH₁₁ or TEM₀₀ mode oscillation. Gaussian mode operation is discussed and practical consequences of this type of operation are demonstrated.     

Current CO2 laser surgery

With the development of suitable instrumentation, human-engineered to fulfil the requirements of the clinical surgeon and designed to fit in with the physical conditions prevailing in the operating theatre, laser surgery has advanced rapidly in the past few years. It shows signs of even more rapid progress and general acceptance as its application and advantages in more and more fields of surgery are demonstrated.     

High repetition-rate and quasi-cw operation of a waveguide CO2 TE laser

We report operation of a waveguide CO₂ TE laser at excitation pulse repetition frequencies as high as 40 kHz. Quasi-continuous laser output was obtained yielding an average output power of 1.5 W from an active volume of 0.1 cc. Details of laser construction and excitation circuitry are given.     

Advanced CO2 laser rangefinders

Factors affecting the design of compact heterodyne- and direct-detection systems are contrasted. Recent UK achievements are placed in context: a TEA laser direct-detection rangefinder and a chirp-pulse-comparison rangefinder-velocimeter are described.     

Absolute frequencies of CO2 laser transitions by multiplication of CO2 laser difference frequencies

Frequencies of CO₂ laser transitions have been compared to the Cs standard by a four-step frequency chain using difference-frequencies from five CO₂ isotope lasers. A tungsten-nickel diode generates the differences and their harmonics. Measurement of the 10.71 μm R(6) transition of ¹³C¹⁸O₂ is described. The absolute frequency was found to be 27 979 469.512(65) MHz. Simultaneously, the four other CO₂ frequencies in the chain were also determined.