Device and method for interaction between an agile laser beam and a hyperfine energy transition of a chemical species

A device for interaction between a laser beam and a hyperfine energy transition of a chemical species placed in a vacuum space, comprising:

• a laser source (19) adapted to emit a source laser beam at an initial optical frequency (ωo),
• wherein the device further includes:
• a single sideband electro-optic modulator (55) comprising an input optical waveguide (57) adapted to receive the source laser beam and an output optical waveguide adapted to generate an output laser beam, the electro-optic modulator (55) having a first high-frequency electrode (62a), another high-frequency electrode (62b) and a plurality of low-frequency electrodes (63a, 63b, 64),
• a low-frequency voltage generator (79), configured to apply on each of said low-frequency electrodes a low-frequency voltage adapted to generate a predetermined optical phase-shift in the optical waveguide, and
• an electronic system (75, 76) comprising a clock, the electronic system (75, 76) being adapted to generate a first electrical signal (sin(Ωt), sin(Ω1t)) modulated at a first pulse (Ω, Ω1) and, respectively, another electrical signal (cos(Ωt), cos(Ω1t)) modulated at the first pulse (Ω, Ω1), synchronized by the clock, the electronic system (75, 76) being adapted to amplitude and phase-tune the first modulated electrical signal (sin(Ωt), sin(Ω1t)) with respect to the other electrical signal (cos(Ωt), cos(Ω1t)) modulated at the first pulse (Ω, Ω1), the electronic system (75, 76) being adapted to simultaneously apply the first electrical signal (sin(Ωt), sin(Ω1t)) modulated at the first pulse (Ω, Ω1) to the first high-frequency electrode (62a) and, respectively, the other electrical signal (cos(Ωt), cos (Ω1t)) modulated at the first pulse (Ω, Ω1) to the other high-frequency electrode (62b), and the electronic system (75, 76) being adapted to switch and tune the first pulse (Ω, Ω1) in a microwave spectral range extending over at most 100 gigahertz so as to frequency-switch the output laser beam to a first optical frequency (ωo+Ω, ωo+Ω1, ωo−Ω, ωo-Ω1) shifted by the first pulse (Ω, Ω1) with respect to the initial optical frequency (ωo) while attenuating the output laser beam at the initial optical frequency (ωo) and at the other harmonics of the first pulse (Ω, Ω1) with respect to the initial optical frequency (ωo), wherein the electronic system (75, 76) includes a radiofrequency electronic synthesizer (75) adapted to generate an electrical signal modulated at the first pulse (Ω, Ω1) and a hybrid coupler (76) having a first output channel (77) and a second output channel (78), the first output channel (77) being electrically connected to the first high-frequency electrode (62a), and respectively, the second output channel (78) being electrically connected to the other high-frequency electrode (62b), the hybrid coupler (76) being adapted to receive the electrical signal modulated at the first pulse (Ω, Ω1) and to generate the first electrical signal (sin(Ωt), sin(Ω1t)) modulated at the first pulse (Ω, Ω1) on the first output channel (77) and, respectively, the other electrical signal (cos(Ωt), cos (Ω1t)) modulated at the first pulse (Ω, Ω1), in phase-quadrature, on the second output channel (78).

A method for interaction between a laser beam and a hyperfine energy transition of a chemical species comprising the following steps:

• confining the chemical species (7, 11, 15, 16) in a vacuum space (8),
• emitting a source laser beam at an initial optical frequency (ωo),
• injecting the source laser beam to an input optical waveguide (57) of a single sideband electro-optic modulator (55),
• generating a first electrical signal (sin(Ωt), sin(Ω1t)) modulated at a first pulse (Ω,Ω1) synchronized to a clock and, respectively, another electrical signal (cos(Ωt), cos(Ωt)) modulated at the first pulse (Ω,Ω1) synchronized to the clock, the first pulse (Ω,Ω1) being switchable and tunable in a microwave spectral range extending over at most 100 gigahertz,
• amplitude and phase-tuning the first modulated electrical signal (sin(Ωt), sin(Ω1t)) with respect to the other electrical signal (cos(Ωt), cos(Ω1t)) modulated at the first pulse (Ω,Ω1),
• simultaneously applying the first electrical signal (sin(Ωt), sin (Q modulated at the first pulse (Ω,Ω1) to a first high-frequency electrode (62a) of the electro-optic modulator (55) and, respectively, the other electrical signal (cos(Ωt), cos (Q1t)) modulated at the first pulse (Ω,Ω1) to another high-frequency electrode (62b) of the electro-optic modulator (55) so as to selectively generate, on an output optical waveguide (157) of the electro-optic modulator (55), an output laser beam at a first optical frequency shifted by the first pulse (Ω, Ω1) with respect to the initial optical frequency (ωo) while attenuating the laser beam at the initial optical frequency (ωo) and at the other harmonic frequencies of the first pulse (Ω,Ω1) with respect to the initial optical frequency (ωo),
• optically amplifying (47, 87) the output laser beam to generate a laser beam amplified at the first shifted optical frequency (ωo+Ω, ωo+Ω1, ωo−Ω, ωo−Ω1),
• transmitting the first laser beam amplified at the first optical frequency shifted (ωo+Ω, ωo+Ω1) towards the chemical species (7, 11, 15, 16), for it to interact with a hyperfine energy transition of the chemical species (7, 11, 15, 16),
• generating a second electrical signal (sin(Ω2t)) modulated at a second pulse (Ω2) synchronized to the clock and, respectively, another electrical signal (cos (Ω2t)) modulated at the second pulse (Ω2), synchronized to the clock, the second pulse (Ω2) being switchable and tunable in a microwave spectral range extending over at most 100 gigahertz,
• amplitude and phase-tuning the second electrical signal (sin(Ω2t)) modulated at the second pulse (Ω2) with respect to the first electrical signal (sin(Ωt), sin(Ω1t)) modulated at the first pulse (Ω, Ω1) to form a first electrical signal double-modulated at the first pulse (Ω, Ω1) and the second pulse (Ω2), and amplitude and phase-tuning the other electrical signal modulated (cos(Ω2t)) at the second pulse (Ω2) with respect to the other electrical signal (cos(Ωt), cos (Ω1t)) modulated at the first pulse (Ω, Ω1) to form another electrical signal double-modulated at the first pulse (Ω, Ω1) and the second pulse (Ω2),
• electrical phase-tuning the first double-modulated electrical signal with respect to the other double-modulated electrical signal,
• simultaneously applying the first double-modulated electrical signal to the first high-frequency electrical signal (62a) of the electro-optic modulator (55) and, respectively, the other double-modulated electrical signal to the other high-frequency electrode (62b) of the electro-optic modulator (55) so as to generate on the output optical waveguide (157) of the electro-optic modulator (55), an output laser beam simultaneously switched to the first optical frequency shifted by the first pulse (Ω, Ω1) with respect to the initial optical frequency (ωo) and to a second optical frequency shifted by the second pulse (Ω2) with respect to the initial optical frequency (ωo), the first shifted optical frequency and the second shifted optical frequency being shifted in the same direction with respect to the initial optical frequency (ωo),
• optically amplifying (47, 87) the output laser beam to generate a laser beam simultaneously amplified at the first shifted optical frequency (ωo+Ω, ωo+Q1, ωo−Ω, ωo-Ω1) and at the second shifted optical frequency, and
• transmitting the laser beam simultaneously amplified at the first shifted optical frequency (ωo+Ω, ωo+Q1, ωo−Ω, ωo−Ω1) and at the second shifted optical frequency towards the chemical species (7, 11, 15, 16).