<Tr> <Td> Trivalent uranium doped calcium fluoride (U: CaF) solid - state laser </Td> <Td> 2.5 μm </Td> <Td> Flashlamp </Td> <Td> First 4 - level solid state laser (November 1960) developed by Peter Sorokin and Mirek Stevenson at IBM research labs, second laser invented overall (after Maiman's ruby laser), liquid helium cooled, unused today . (1) </Td> </Tr> <Tr> <Td> Divalent samarium doped calcium fluoride (Sm: CaF) laser </Td> <Td> 708.5 nm </Td> <Td> Flashlamp </Td> <Td> Also invented by Peter Sorokin and Mirek Stevenson at IBM research labs, early 1961 . Liquid helium cooled, unused today . (2) </Td> </Tr> <Tr> <Td> F - Center laser . </Td> <Td> 2.3 - 3.3 μm </Td> <Td> Ion laser </Td> <Td> Spectroscopy </Td> </Tr> <Table> <Tr> <Th> Laser gain medium and type </Th> <Th> Operation wavelength (s) </Th> <Th> Pump source </Th> <Th> Applications and notes </Th> </Tr> <Tr> <Td> Semiconductor laser diode (general information) </Td> <Td> 0.4 - 20 μm, depending on active region material . </Td> <Td> Electrical current </Td> <Td> Telecommunications, holography, printing, weapons, machining, welding, pump sources for other lasers, high beam headlights for automobiles . </Td> </Tr> <Tr> <Td> GaN </Td> <Td> 0.4 μm </Td> <Td> Optical discs. 405 nm is used in Blu - ray Discs reading / recording . </Td> </Tr> <Tr> <Td> InGaN </Td> <Td> 0.4 - 0.5 μm </Td> <Td> Home projector, primary light source for some recent small projectors </Td> </Tr> <Tr> <Td> AlGaInP, AlGaAs </Td> <Td> 0.63 - 0.9 μm </Td> <Td> Optical discs, laser pointers, data communications . 780 nm Compact Disc, 650 nm general DVD player and 635 nm DVD for Authoring recorder laser are the most common lasers type in the world . Solid - state laser pumping, machining, medical . </Td> </Tr> <Tr> <Td> InGaAsP </Td> <Td> 1.0 - 2.1 μm </Td> <Td> Telecommunications, solid - state laser pumping, machining, medical...</Td> </Tr> <Tr> <Td> lead salt </Td> <Td> 3 - 20 μm </Td> <Td> </Td> </Tr> <Tr> <Td> Vertical cavity surface emitting laser (VCSEL) </Td> <Td> 850--1500 nm, depending on material </Td> <Td> Telecommunications </Td> </Tr> <Tr> <Td> Quantum cascade laser </Td> <Td> Mid-infrared to far - infrared . </Td> <Td> Research, Future applications may include collision - avoidance radar, industrial - process control and medical diagnostics such as breath analyzers . </Td> </Tr> <Tr> <Td> Hybrid silicon laser </Td> <Td> Mid-infrared </Td> <Td> Low cost silicon integrated optical communications </Td> </Tr> </Table>

What three types of energy are used in lasing