1887
banner image
No data available.
Please log in to see this content.
You have no subscription access to this content.
No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
Magnetometric sensitivity optimization for nonlinear optical rotation with frequency-modulated light: Rubidium D2 line
Rent:
Rent this article for
USD
10.1063/1.3225917
/content/aip/journal/jap/106/6/10.1063/1.3225917
http://aip.metastore.ingenta.com/content/aip/journal/jap/106/6/10.1063/1.3225917
View: Figures

Figures

Image of FIG. 1.
FIG. 1.

Experimental geometry (known as the Faraday geometry) for measurement of magneto-optical rotation, where in our case the atomic medium is a sample of Rb atoms contained in a paraffin-coated cell. The light propagates along the magnetic field (which defines the longitudinal direction, ). The light is initially linearly polarized along an axis at 45° to the and axes, and the plane of light polarization is rotated by an angle at the output of the medium.

Image of FIG. 2.
FIG. 2.

Schematic diagram of the experimental setup. interferometer, density filter, , splitter, atomic vapor laser lock system (see Refs. 62 and 63), amplifier (analog), control input for PZT affecting extended-cavity diode laser feedback grating angle, control input for modulation of diode laser current, converter, beam splitter (Wollaston), filter.

Image of FIG. 3.
FIG. 3.

NMOR amplitude as a function of longitudinal magnetic field (, along the direction of light propagation), demodulated at the first harmonic of . The upper plot shows the -dependence of the in-phase (, data offset above) and out-of-phase (, data offset below) FM NMOR signal amplitudes when the laser is tuned to the high-frequency side of the Doppler-broadened component of the D2 transition. The lower plot shows the -dependence of the FM NMOR signal amplitudes when the laser is tuned to the high-frequency side of the Doppler-broadened component of the D2 transition. The light power is , the modulation amplitude , the modulation frequency , and the cell temperature was for which the Rb vapor density was measured to be by fitting a low-light-power absorption spectrum to a Voigt profile. The FM NMOR resonances at are denoted the resonances, and the resonances at are denoted the resonances (where ).

Image of FIG. 4.
FIG. 4.

FM NMOR ( resonance) amplitude as a function of modulation frequency for longitudinal field , laser tuned to the high-frequency side of the Doppler-broadened component of the D2 transition. The light power is , the modulation amplitude and the cell temperature was for which the Rb vapor density was measured to be . signal is offset from zero due to background rotation from the NMOR transit effect resonance, signal has negligible offset because there is no component for the transit effect resonance.

Image of FIG. 5.
FIG. 5.

Laser-detuning dependence of FM NMOR signals for incident light power (left plots) and light power (right plots). Laser modulation parameters are and , and the cell temperature , corresponding to a vapor density of . The signals are characterized by the derivative of the optical rotation amplitude with respect to longitudinal field ( in units of rad/G) and the signals are characterized by their amplitude (mrad). Transmission spectra (with no frequency modulation) are shown at bottom, with arrows indicating the central frequencies of the various Doppler-broadened hyperfine components of the D2 transition.

Image of FIG. 6.
FIG. 6.

Illustration of the time-dependent optical pumping and optical rotation generated via frequency modulation for low-light-power (where alignment-to-orientation can be neglected and optical rotation is of opposite sign for transitions as compared to , transitions, see text). The diagram on the left-hand side illustrates the pump and probe modulation when the center frequency of the laser light is tuned to the center of the Doppler-broadened transition, the diagram on the right-hand side illustrates pump and probe modulation when the laser light is detuned to the wing of the resonance. Note that pump modulation is at the second harmonic of the frequency modulation when the laser light is tuned to the center of the resonance. Arrows at the base of the probing interaction diagram indicate the approximate central frequencies and estimated relative contribution of different hyperfine components to the overall Doppler-broadened optical rotation spectrum.

Image of FIG. 7.
FIG. 7.

Laser detuning dependence of the derivative of the signal optical rotation amplitude with respect to longitudinal field ( in units of rad/G) for and resonances (left and right plots, respectively) for various light powers. Laser modulation parameters are and , and the cell temperature , corresponding to a vapor density of . For the resonances shown in the plots on the right-hand side, data for (open circles) are acquired at and data for (filled circles) are acquired at . Transmission spectra for light power (with no frequency modulation) are shown at bottom. Only and components of the D2 transition are shown.

Image of FIG. 8.
FIG. 8.

Illustration of the time-dependent optical pumping and optical rotation generated via frequency modulation for high-light-power (where alignment-to-orientation is the dominant cause of optical rotation, causing enhanced rotation for transitions with the same sign as compared to , transitions, see text). Arrows at the base of the probing interaction diagram indicate the approximate central frequencies and estimated relative contribution of different hyperfine components to the overall Doppler-broadened optical rotation spectrum.

Image of FIG. 9.
FIG. 9.

Upper plot shows the pump-light-power dependence of the normalized, detuning-optimized amplitude of optical rotation for an unmodulated probe beam measured at the first harmonic of (open circles, dashed line to guide the eyes) and an asynchronously modulated probe beam measured at the first harmonic of (filled circles, solid line to guide the eyes). The 795-nm-probe beam measured the optical rotation spectrum for the Rb D1 line, and the probe light power in both cases was . The unmodulated probe beam is principally sensitive to atomic alignment transverse to precessing at while the asynchronously modulated probe beam is principally sensitive to static atomic orientation along . The pump beam was tuned to the maximum of rotation for the component of the D2 line and frequency-modulated at with . The lower plot shows the dependence of the detuning-optimized amplitude of the FM NMOR signal slope for the resonance.

Image of FIG. 10.
FIG. 10.

Laser detuning dependence of the derivative of the signal optical rotation amplitude with respect to longitudinal field ( in units of rad/G) for and resonances (left and right plots, respectively) for various modulation amplitudes . Laser modulation parameters are and light power , and the cell temperature , corresponding to a vapor density of . For the resonances shown in the plots on the right-hand side, data for (open circles) are acquired at and data for (filled circles) are acquired at . Transmission spectra for light power (with no frequency modulation) are shown at bottom. Only and components of the D2 transition are shown.

Image of FIG. 11.
FIG. 11.

Upper plots show laser-detuning-optimized SNP sensitivity as a function of incident light power for both the and signals. Lower plots show the relative detuning at which the optimum sensitivity is achieved (zero detuning is defined to be at the center of the Doppler-broadened transition—see, for example, Fig. 5). Data acquired for cell temperature , corresponding to a vapor density of , , and .

Image of FIG. 12.
FIG. 12.

Upper plots show laser-detuning-optimized SNP sensitivity as a function of modulation amplitude for both the and signals. Lower plots show the relative detuning at which the optimum sensitivity is achieved (zero detuning is defined to be at the center of the Doppler-broadened transition—see, for example, Fig. 5). Data acquired for cell temperature , corresponding to a vapor density of , , and incident laser light power .

Image of FIG. 13.
FIG. 13.

Magnetometric sensitivity as a function of detuning from the center of the Doppler-broadened resonance. Filled circles (blue) show sensitivity for cell temperature and Rb vapor density , incident laser light power , modulation amplitude , and . Open circles (red) show sensitivity for cell temperature and Rb vapor density , incident laser light power , modulation amplitude , and . Note that the SNP magnetometric sensitivity spectra reflect differences between the FM NMOR spectra at different Rb vapor densities, light powers, and modulation amplitudes.

Loading

Article metrics loading...

/content/aip/journal/jap/106/6/10.1063/1.3225917
2009-09-24
2014-04-17
Loading

Full text loading...

This is a required field
Please enter a valid email address
752b84549af89a08dbdd7fdb8b9568b5 journal.articlezxybnytfddd
Scitation: Magnetometric sensitivity optimization for nonlinear optical rotation with frequency-modulated light: Rubidium D2 line
http://aip.metastore.ingenta.com/content/aip/journal/jap/106/6/10.1063/1.3225917
10.1063/1.3225917
SEARCH_EXPAND_ITEM