PHYSICS DEPARTMENT. RUBY LASER. TOPICS TO BE DISCUSSED. HISTORY CHARACTERSTICS CONSTRUCTION PRINCIPLE AND WORKING SPIKING THRESHOLD POWER APPLICATIONS. HISTORY. The first laser to be operated successfully was the Ruby laser which was fabricated by Maiman in 1960. CHARACTERSTICS.
was the Ruby laser which was fabricated by Maimanin 1960.
The Ruby laser consist of a single ruby crystal in the form of a cyclinderical rod of length about 5cm and diameter 0.5 cm. Its end surfaces are accurately plane and parrallel.
One of the ends is silvered with 100% reflectivity and the other end with 10% transmission . The two ends thus form a resonant cavity.
The Ruby rod is placed inside a Xenon flash lamp.
The flash lamp is connected to a capacitor which discharges a few thousand joules of energy in a few miliseconds.This results in power output of a few megawatt from Xenon lamp.
1) Ruby consists of aluminium oxide(Al2O3) in which some of of the aluminium ions are replaced by chromium.For good lasing action,about 0.05% of the atoms are that of chromium . Hence it is called pink ruby.
3) There are to main pump bands ( called the blue band & green band).4f1 & 4f2 centered at 0.42 μm & 0.55μm respectively. These bands are about 1000Å wide each and they have a very small lifetime (≤10-9s)
4) Chromium ions gets excited to these levels by absorbing energy from xenon flash lamp (i.e. optical pumping). There is a fast non-radiative decay from these bands to 2E-state, which is a meta-stable state and has a life time of 3*10-3 s.The metastable level 2E is split into two sub levels with a separation of ΔE=29 cm-1.
5)Thus ,population inversion takes between 2Ā and Ē levels and the ground state 4A2 emitting a sharp doublet R1( λ=6943Å)and R2(λ=6928Å) lines.