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Frequency Tripling of Frequency Tunable Laser

IP.com Disclosure Number: IPCOM000078309D
Original Publication Date: 1972-Dec-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Armstrong, JA: AUTHOR [+5]

Abstract

A means for obtaining the tripled frequency of a fundamental laser frequency has been devised that employs a tunable dye laser as the fundamental frequency to be tripled, so as to diminish the power needed in that fundamental frequency as compared to the use of an untuned laser for obtaining frequency tripling.

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Frequency Tripling of Frequency Tunable Laser

A means for obtaining the tripled frequency of a fundamental laser frequency has been devised that employs a tunable dye laser as the fundamental frequency to be tripled, so as to diminish the power needed in that fundamental frequency as compared to the use of an untuned laser for obtaining frequency tripling.

Fig. 1A depicts a simplified energy level diagram of an atom or molecule, and states 1, 2, 3, and 4 are connected by dipole matrix elements <1/2>. <2/3>, etc. In the prior art, the irradiation of metal vapors with high-power lasers can cause the third harmonic to be generated, if a rare gas is mixed with the metal vapor to achieve phase matching between the first and third harmonics generated in the vapor. As seen in Fig. 1B, the vapor used will consist of atoms or molecules having a nonlinear third-harmonic susceptibility.

It is known that the susceptibility is proportional to <1/2> <2/3> <3/4> <4/1> over DeltaE(1), DeltaE(2), DeltaE(3). plus the sum over similar expressions. where <1/2> <2/3>, etc. are the dipole matrix elements connecting the ground state (1) with an excited state. The energy defects DeltaE(1), DeltaE(2), DeltaE(3) are, respectively, E(2)-E(1)hV, E(3)-E(1)-2hV,and E(4)-E(1)-3hV. The sum is taken over all energy states of the atom or the molecule.

One term of this sum is maximized by changing hv so that an energy defect approaches zero. The optimum case is to use, as shown in Fig. 2, a tunable lase...