Generation Of Solid-state Lasers Research Articles

Bound soliton formation in a SESAM mode-locked Cr:ZnSe laser with birefringent plates

We report on experimental observation of four phase-locked bound soliton formation in a SESAM mode-locked $$\hbox {Cr}^{2+}$$ :ZnSe laser with an output power of 20 mW, a temporal pulse-to-pulse separation of 18.2 ps and single pulse duration of 1.4 ps. We demonstrate that birefringence can be used as an efficient mechanism to achieve bound state generation in solid-state lasers as an alternative method to Kerr-lens and SESAM saturation by a pump power increase or a total net cavity dispersion variation. In this work, we consider two different setup configurations to demonstrate the birefringence influence on bound soliton formation. The suggested technique could be effectively used in the realization of mode-locked lasers based on solid-state active media operating in bound-state or multi-bound regimes.

High-pressure and optical properties of LaMgAl11O19:Sm3+ laser material

Emission spectra and decay properties of the 4G 5/2 level of Sm3+ ions in LaMgAl11O19:Sm3+ (LMA:Sm3+) have been measured as functions of pressure up to 100 kbar at room temperature. Changes of the positions of three considered fluorescence lines (560, 606, and 643 nm) under pressure are very small. The fourth one (594 nm) is practically insensitive upon pressure and has a red shift rate (RSR) close to zero. Fluorescence lifetime τ for the 594 nm line decreases non-linearly with pressure in the considered pressure range. Effect of the pressure on τ was described using a model which considered the change of the inter-ionic distance (r), ionic polarizability (α), and material refractive index (n) with pressure. Calculated pressure-induced change of the lifetime τ is in good agreement with the experimental data. Insensitivity of the lines position upon the pressure, and small RSR, leads to conclusion that LMA:Sm3+ can be the base for a new generation of solid state lasers with numerous applications.

Minimizing Heat Generation in Solid-State Lasers

Novel high-power ytterbium YAG lasers are described. These lasers incorporate the principle of anti-Stokes fluorescence cooling to reduce or eliminate detrimental heating. Lasers with net heating and net cooling are demonstrated. By balancing the spontaneous and stimulated emission, we have reduced the net thermal loading to below 0.01% of the laser's average output power. Design, testing, and analysis are reported for lasers up to 500 W average power and pulsed operation up to 30 s. Issues and limitations of this approach are discussed.

Solid-state lasers: status and perspectives

Diode-pumped solid-state lasers are attractive sources of coherent radiation for various scientific and technological applications. In the past years these lasers have emerged as attractive power scalable laser concept for continuous wave and pulse operation. However, the different fields of applications increasingly demand more powerful, efficient, and rugged lasers with diffraction limited beam quality in a wide spectral range. Hence, at present a new generation of solidstate lasers is in the focus of the developments. Thin disc and fiber lasers with improved thermo-optical parameters have now entered the regime of multi-kilowatt of average

Properties and Prospects of High Brightness Solid State Lasers

AbstractThe new generation of solid state lasers like disc and fiber lasers showed an extraordinary quick development with respect to power, beam quality and price. It is shown that recent technology enables welding with a considerable lower energy consumption than for conventional gas metal arc welding. Besides the efficiency, the most important feature is the beam quality, which can be used for remote applications and welding at high speed. on the other hand, some challenges have to be solved, like thermal distortion of the beam shaping optics, humping and low homogeneity of the welds.

Ray guns get real

Cheap rockets fired by insurgents are taking a deadly toll in the Middle East. The article looks at whether a new generation of solid-state lasers can blow them out of the sky.

Quasi-soliton generation in solid-state lasers with a semiconductor absorber

The theory of a self-consistent laser field is used as the basis for investigating a mode-locking mechanism by means of the formation of a quasi-Schrödinger soliton in a cw solid-state laser with a saturable semiconductor shutter. The studies include possible soliton-destabilization regimes, the abrupt transition from femto- to picosecond lasing, the appearance of autovibrations, and also the breaking off of pulse generation. It is shown that multistable states and hysteresis phenomena exist during the adjustment of group-velocity dispersion and pump power. © 2004 Optical Society of America

Semiconductor saturable absorber mirrors (SESAM's) for femtosecond to nanosecond pulse generation in solid-state lasers

Intracavity semiconductor saturable absorber mirrors (SESAM's) offer unique and exciting possibilities for passively pulsed solid-state laser systems, extending from Q-switched pulses in the nanosecond and picosecond regime to mode-locked pulses from 10's of picoseconds to sub-10 fs. This paper reviews the design requirements of SESAM's for stable pulse generation in both the mode-locked and Q-switched regime. The combination of device structure and material parameters for SESAM's provide sufficient design freedom to choose key parameters such as recovery time, saturation intensity, and saturation fluence, in a compact structure with low insertion loss. We have been able to demonstrate, for example, passive modelocking (with no Q-switching) using an intracavity saturable absorber in solid-state lasers with long upper state lifetimes (e.g., 1-/spl mu/m neodymium transitions), Kerr lens modelocking assisted with pulsewidths as short as 6.5 fs from a Ti:sapphire laser-the shortest pulses ever produced directly out of a laser without any external pulse compression, and passive Q-switching with pulses as short as 56 ps-the shortest pulses ever produced directly from a Q-switched solid-state laser. Diode-pumping of such lasers is leading to practical, real-world ultrafast sources, and we will review results on diode-pumped Cr:LiSAF, Nd:glass, Yb:YAG, Nd:YAG, Nd:YLF, Nd:LSB, and Nd:YVO/sub 4/.

Bi-directional transmission of molecular information by photon or electron beams passing in the close vicinity of specific molecules, and its clinical and basic research applications: 1) Diagnosis of humans or animal patients without any direct contact; 2) Light microscopic and electron microscopic localization of neuro-transmitters, heavy metals, Oncogen C-fos (AB2), etc. of intracellular fine structures of normal and abnormal single

In 1985, Omura, Y. discovered that, when specific molecules were placed anywhere in the close vicinity of the path of a light beam (laser), their molecular information, as well as information on electrical & magnetic fields, is transmitted bi-directionally along the path of this light beam. Namely, this information is transmitted in the direction the light beam is projected and towards the direction from which the light beam is coming. This finding was applied to the following clinical and basic research: 1) In the past, using indirect Bi-Digital O-Ring Test, human or animal patients were diagnosed through an intermediate third person holding a good electrical conducting probe, the tip of which was touching the part of the patient to be examined. However, in order to diagnose the patient in isolation from a distance, or a dangerous or unmanagable unanesthesized animal, such as a lion or tiger, the author succeeded in making a diagnosis by replacing the metal conducting probe with a soft laser beam which is held by the one hand of the third person whose index finger is placed in close vicinity of the laser beam generated by a battery-powered penlight-type solid state laser generator. Thus, diagnosis within visible distance, without direct patient contact, became a reality. 2) Using a projection light microscope, by giving indirect Bi-Digital O-Ring Test while contacting with a fine electro-conductive probe on the magnified fine structure of normal and abnormal cells, various normal and abnormal intracellular substances were localized through a third person holding a pure reference control substance with the same hand that is holding the probe as an intermediary for the indirect Bi-Digital O-Ring Test. Instead of the photon beam in a light microscope, the author found that, using an electron beam passing through the close vicinity of specific molecules of specimens in an electron microscope, the molecular information is transmitted to the magnified fluorescent screen, and an indirect Bi-Digital O-Ring Test could be performed through a projected penlight-type solid state soft laser beam on the magnified intracellular structure through an observation glass window. Using the magnified fine structure of the cells, by either a light projection microscopic field or electron microscope, in various cancer cells of both humans and animals, Oncogen C-fos (AB2) and mercury were found inside of the nucleus. Integrin alpha 5 beta 1 was found on cell membranes and nuclear cell membranes of cancer cells. Acetylcholine was not found anywhere within cancer cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Femtosecond pulse generation in Ti:Al_2O_3 using a microdot mirror mode locker

A new nonlinear intracavity device called a microdot mirror mode locker is demonstrated for ultrashort-pulse generation in solid-state lasers. The microdot mirror produces fast saturable absorber action by using self-focusing. Pulse durations of 190 fs are achieved in a Ti:A1(2)O(3) laser. The microdot mirror mode locker is modular, preserves wavelength tunability, and can be extended to a wide range of solid-state lasers.

Short pulse generation in solid state lasers by a novel passive technique

A novel passive Q-switching technique based on self focusing is studied theoretically and experimentally. In this paper we present results obtained with a simple aberrationless gaussian model that describes the short pulse generation dynamics for different cavity configurations and different nonlinear characteristics of the focusing medium. Experimental results are also presented that are in good agreement with the predictions of the theoretical model. Preliminary results in ultrashort pulse generation are also presented.

Ultrashort pulse generation in solid-state lasers.

Ultrashort pulse generation in solid-state lasers.

A new generation of solid-state lasers

A discussion is presented of recent advances in research and development relating to highefficiency lasers made from activated ionic crystals (specifically, gadolinium-scandium-gallium garnet activated by Nd3+ and Cr3+ and yttrium aluminum garnet activated by Er3+) and multicomponent glasses activated by Nd3+, Er3+ and Yb3+, along with tunable color-center lasers made from lithium fluoride. The physical processes, which occur in these active crystals and which lead to enhanced population inversion associated with the laser transition, are discussed, including energy transfer from sensitizer ions to active ions and cross-relaxation between the level systems of neighboring active ions. Processes that give rise to increased efficiency in tunable color-center lasers based on LiF crystals are analyzed; also mentioned is work relating to the fabrication of passive Q switches using LiF crystals with F2– color centers.

Novoe pokolenie tverdotel'nykh lazerov

Novoe pokolenie tverdotel'nykh lazerov

The generation of picosecond pulses in actively mode-locked c.w. solid-state lasers. IV. The pulse formation†

This paper is the last in a series of four dealing with the problem of picosecond pulse generation in solid-state lasers. It is primarily concerned with active (as opposed to passive) modo-locking, and in particular with the early stages of the mode-locking process. The discussion is based on an aeousto-optic (loss) modulator and its interaction with the radiation present inside a laser cavity, from the moment the modulator is switched on until a fully modo-lockod pulso is formed. A brief discussion of the properties of loss modulators is alao included. The investigations have been carried out with the help of a computer model of the system, a typical Nd : YAG laser serving as an example. It is assumed that the laser radiation is composed initially of a large number of cavity modes (typically 30–100). their phases being distributed at random (narrow-bond noise). The mechanism of a gradual build-up of mode-locking under the influence of a loss modulator is carefully investigated using both the time-domain ...

Nanosecond and microsecond pulse generation in solid-state lasers (review)

The temporal characteristics of Q-switched laser pulses are considered. The dependences are given of the duration (Δτ) and shape of pulses from solid-state lasers, operating in the giant-pulse regime, on the active-medium and resonator parameters, and the possibilities of varying Δτ over the range 10–9–10–6 sec are considered. Attention is concentrated on the possibilities of increasing the duration of a pulse to 1 μsec and more. Theoretical and experimental results are presented on the subject of increasing the pulse duration by introducing, into the laser cavity, electro-optic negative feedback or nonlinear losses caused by two-photon absorption in semiconductors, stimulated Raman scattering, and second harmonic generation. Methods are also considered of reducing Δτ for a giant pulse to 10–9 sec or less.