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Practicality and versatility of Ti: Sapphire lasers
Ti: Sapphire lasers are becoming more and more practical due to the recent advances of turnkey, hands-free, commercially available, and diode-pumped lasers. The extended tunability of these lasers has enabled the use of various dyes with distinct absorption spectra and chemical properties. Ti: Sapphire lasers have been instrumental in different specialty areas, such as nonlinear physics and terahertz generation. It is also being used for cold micromachining, where the cutting, drilling, and scribing are free of undesirable thermal effects. In other words, Ti: Sapphire lasers and based on them laser systems are unsurpassed in their extraordinary breadth of performance and resulting diversity of applications.
Historical development and technical characteristics
Titanium-doped sapphire lasers and amplifiers have enabled countless applications in fundamental research in physics, biology, and chemistry since their invention in the early 1980s. Ti: Sapphire lasers play an important role across a wide range of photonics applications, including multicolor ultrafast spectroscopy, multiphoton deep-tissue imaging, terawatt and petawatt physics, and “cold” micromachining.
Laser properties and operation
Speaking specifically, Ti: Sapphire lasers are tunable fiber lasers which emit red and near-infrared light in the range from 650 to 1100 nanometers. These lasers are mainly used in scientific research because of their tunability and their ability to generate ultrashort pulses. Ti: Sapphire lasers possess high laser cross sections, which in turn minimize their Q-switching instabilities. Pumping of Ti: Sapphire lasers is carried out with other lasers having wavelengths of 514 to 532 nm: it includes Nd:YVO lasers, frequency-doubled Nd:YAG lasers, or argon-ion lasers.
Historical milestones
The first reported Ti: Sapphire laser operation was performed in June 1982 by Peter Moulton at the 12th International Quantum Electronics Conference in Munich, Germany. In 1998, Spectra-Physics offered the first commercial Ti: Sapphire laser, a broadly tunable continuous-wave model, and, in late 1990, the first ultrafast Ti: Sapphire laser, a picosecond mode-locked oscillator. Further developments in this field led to a sudden paradigm shift rarely seen in research. Ti: Sapphire laser systems are unmatched in their characteristics for delivering a combination of broad spectral bandwidth, a range of repetition rates, wide tunability, and high-average-power levels. Since most other broadband lasers gain media have relatively poor thermal properties, Ti: Sapphire lasers offer a unique performance for use in ultrafast laser systems.
Applications of Ti: Sapphire lasers
The main applications of Ti: Sapphire lasers are in research laboratories, in particular in spectroscopy. The large tuning range makes these fiber lasers attractive for generating tunable sub-picosecond pulses at short wavelengths.
Use in atmospheric and chemical research
Ti: Sapphire lasers are used in NASA (Lidar Atmospheric Sensing Experiment) for measuring water vapor and aerosols, and their effects on atmospheric processes. Also, Ti: Sapphire laser systems are used to study chemical reactions on ultrafast time scales. Recently, devices to control and measure the spectral phase and amplitude of the ultrafast pulses have been developed in order to find applications in the field of coherent control, which has grown increasingly sophisticated in recent days.
Use in biological research
In biology, Ti: Sapphire lasers are instrumental in multiphoton microscopy (MPM), which has developed into the leading noninvasive laboratory tool for studying underlying biological phenomena. This tool offers high-resolution three-dimensional imaging in thick tissues, including in vivo specimens.
Use in physics and industrial applications
Ti: Sapphire lasers have been instrumental in fields such as nonlinear physics and terahertz generation. The ability of Ti: Sapphire lasers to generate ultrafast pulses and wide wavelength tunability enables unprecedented advances across a range of disciplines in science, industry, and beyond.