Taking advantages of ultra-narrow bandwidth and high noise rejection performance of the Faraday anomalous dispersion optical filter (FADOF), simultaneously with the coherent amplification of atomic stimulated emission, a stimulated amplified Faraday anomalous dispersion optical filter (SAFADOF) at cesium 1470 nm is realized. The SAFADOF is able to significantly amplify very weak laser signals and reject noise in order to obtain clean signals in strong background. Experiment results show that, for a weak signal of 50 pW, the gain factor can be larger than 25000 (44 dB) within a bandwidth as narrow as 13 MHz. Having this ability to amplify weak signals with low background contribution, the SAFADOF finds outstanding potential applications in weak signal detections.Taking advantages of ultra-narrow bandwidth and high noise rejection performance of the Faraday anomalous dispersion optical filter (FADOF), simultaneously with the coherent amplification of atomic stimulated emission, a stimulated amplified Faraday anomalous dispersion optical filter (SAFADOF) at cesium 1470 nm is realized. The SAFADOF is able to significantly amplify very weak laser signals and reject noise in order to obtain clean signals in strong background. Experiment results show that, for a weak signal of 50 pW, the gain factor can be larger than 25000 (44 dB) within a bandwidth as narrow as 13 MHz. Having this ability to amplify weak signals with low background contribution, the SAFADOF finds outstanding potential applications in weak signal detections.

arXiv:1710.04768Oct 13, 20170 citations

Atomic filter based on stimulated Raman transition at the rubidium D1 line

Xiuchao Zhao, Xianping Sun, Maohua Zhu +3 more

We report on a 795 nm atomic filter consisting of a stimulated Raman gain amplifier together with normal Faraday anomalous dispersion optical filtering (FADOF) at the rubidium D1 line. The filter is operated with a single transmission peak. The gain of the filter's transmission light signal is enhanced up to 85-fold compared to case operating without a stimulated Raman transition. Based on atomic coherence, the filter's minimum transmission bandwidth is less than 22 MHz. In each filtering channel, the signal light's frequency can be tuned by changing the detuning of the coupling light. Such a filter with stimulated Raman gain is more efficient in extracting weak signals in the presence of a strong light background compared with the normal FADOF. This expands the range of potential applications in optical communications and lidar technology. This filtering method can also be extended to the lines of other atoms.We report on a 795 nm atomic filter consisting of a stimulated Raman gain amplifier together with normal Faraday anomalous dispersion optical filtering (FADOF) at the rubidium D1 line. The filter is operated with a single transmission peak. The gain of the filter's transmission light signal is enhanced up to 85-fold compared to case operating without a stimulated Raman transition. Based on atomic coherence, the filter's minimum transmission bandwidth is less than 22 MHz. In each filtering channel, the signal light's frequency can be tuned by changing the detuning of the coupling light. Such a filter with stimulated Raman gain is more efficient in extracting weak signals in the presence of a strong light background compared with the normal FADOF. This expands the range of potential applications in optical communications and lidar technology. This filtering method can also be extended to the lines of other atoms.

Optics ExpressJul 1, 20158 citations

420-nm Faraday Optical Filter With 2.7-MHz Ultranarrow Bandwidth Based on Laser Cooled 87Rb Atoms

Xiaolei Guan, Wei Zhuang, Tiantian Shi +4 more

Using laser cooling technology, we demonstrate an ultranarrow-bandwidth Faraday anomalous dispersion optical filter (FADOF) which operates on the $5^{2}\text{S}_{1/2}$ ( $F = 2$ ) to $6^{2}\text{P}_{3/2}$ ( $F' = 3$ ) transition at 420 nm based on cold 87Rb atoms. The filter achieves a single 2.7(2) MHz passband at a peak transmission of 3.2%. It is the narrowest bandwidth FADOF known at present, as the influence of Doppler broadening on the bandwidth narrowing of FADOF is effectively overcome by cold atoms. This ultranarrow-bandwidth FADOF has a figure of merit (FOM) value of 11.85 GHz−1, which is seven times larger than the largest FOM achieved by thermal vapor atomic optical filter published to date. Furthermore, the scheme can be extended to almost all kinds of atomic optical filters and may find applications in active Faraday optical frequency standard and self-stabilizing laser.Using laser cooling technology, we demonstrate an ultranarrow-bandwidth Faraday anomalous dispersion optical filter (FADOF) which operates on the$5^{2}\text{S}_{1/2}$($F = 2$) to$6^{2}\text{P}_{3/2}$($F' = 3$) transition at 420 nm based on cold 87Rb atoms. The filter achieves a single 2.7(2) MHz passband at a peak transmission of 3.2%. It is the narrowest bandwidth FADOF known at present, as the influence of Doppler broadening on the bandwidth narrowing of FADOF is effectively overcome by cold atoms. This ultranarrow-bandwidth FADOF has a figure of merit (FOM) value of 11.85 GHz−1, which is seven times larger than the largest FOM achieved by thermal vapor atomic optical filter published to date. Furthermore, the scheme can be extended to almost all kinds of atomic optical filters and may find applications in active Faraday optical frequency standard and self-stabilizing laser.

IEEE Photonics Technology LettersMay 1, 20239 citations

Ultranarrow faraday rotation filter at the rb d1 line

Joanna A. Zielińska, Federica A. Beduini, Nicolas Godbout +1 more

We present a theoretical and experimental study of the ultra-narrow bandwidth Faraday anomalous dispersion optical filter (FADOF) operating at the rubidium D1 line (795 nm). This atomic line gives better performance than other lines for the main FADOF figures of merit, e.g. simultaneously 71 % transmission, 445MHz bandwidth and 1.2GHz equivalent noise bandwidth. c © 2013 Optical Society of America OCIS codes: 020.1335, 010.3640 Ultra-narrow bandwidth optical filters are key el-ements in laser remote sensing (LIDAR), observa-tional astronomy, free-space communications and quan-tum optics. Relative to conventional interference fil-ters, FADOFs offer high background-rejection, mechani-cal robustness, imaging capability and high transmission. FADOFs have been developed for several alkali atom res-onances – Cs D2 [1] and 6S1/2 → 7P3/2 [2] lines, Rb D2 line [3, 4], K (three lines) [5], Na D lines [6], and for Ca [7]. We demonstrate a FADOF on the D1 line of Rb (wave-length 795 nm). This line, efficiently detected with Si detectors, accessible with a variety of laser technolo-gies, and with large hyperfine splittings, is a favorite for coherent and quantum optics with warm atomic va-pors. Applications include electromagnetically-induced transparency [8], stopped light [9], optical magnetom-etry [10, 11], laser oscillators [12], polarization squeez-ing [13, 14], quantum memory [15] and high-coherence heralded single photons [16,17]. Here we show that the Rb D1 line provides supe-rior FADOF performance. We demonstrate a FADOF surpassing other atoms and other Rb transitions for key figures of merit, including peak transmission Tmax, transmission bandwidth and equivalent noise bandwidth ENBW = T−1max T (ν)dν, where T (ν) is the filter trans-mission versus frequency ν [4].We present a theoretical and experimental study of the ultra-narrow bandwidth Faraday anomalous dispersion optical filter (FADOF) operating at the rubidium D1 line (795 nm). This atomic line gives better performance than other lines for the main FADOF figures of merit, e.g. simultaneously 71 % transmission, 445MHz bandwidth and 1.2GHz equivalent noise bandwidth. c © 2013 Optical Society of America OCIS codes: 020.1335, 010.3640 Ultra-narrow bandwidth optical filters are key el-ements in laser remote sensing (LIDAR), observa-tional astronomy, free-space communications and quan-tum optics. Relative to conventional interference fil-ters, FADOFs offer high background-rejection, mechani-cal robustness, imaging capability and high transmission. FADOFs have been developed for several alkali atom res-onances – Cs D2 [1] and 6S1/2 → 7P3/2 [2] lines, Rb D2 line [3, 4], K (three lines) [5], Na D lines [6], and for Ca [7]. We demonstrate a FADOF on the D1 line of Rb (wave-length 795 nm). This line, efficiently detected with Si detectors, accessible with a variety of laser technolo-gies, and with large hyperfine splittings, is a favorite for coherent and quantum optics with warm atomic va-pors. Applications include electromagnetically-induced transparency [8], stopped light [9], optical magnetom-etry [10, 11], laser oscillators [12], polarization squeez-ing [13, 14], quantum memory [15] and high-coherence heralded single photons [16,17]. Here we show that the Rb D1 line provides supe-rior FADOF performance. We demonstrate a FADOF surpassing other atoms and other Rb transitions for key figures of merit, including peak transmission Tmax, transmission bandwidth and equivalent noise bandwidth ENBW = T−1max T (ν)dν, where T (ν) is the filter trans-mission versus frequency ν [4].

Jan 1, 201287 citations

Faraday Anomalous Dispersion Optical Filter at the 87Rb D1 Line

刘阳 LIU Yang, 闫西章 YAN Xi-zhang, 王潇潇 WANG Xiao-xiao +1 more

To obtain the weak signal light detection from the high background noise,a study on ultra-narrow bandwidth Faraday anomalous dispersion optical filter(FADOF) at the 87Rb D1 line,5S1/2F=2→5P1/2 F′=1transmission(795 nm) is demonstrated experimentally.A sample cell filled with Rubidium atoms in which the proportion of 87Rb is greater than that of the nature rubidium is placed in a homogeneous magnetic field between two crossed Glan-Thompson polarizers.The incident probe light goes through the sample cell,and interacts with the atoms.Because of the Faraday rotation,the function of the filter can be realized.When the experiment condition changed,the result of transmission spectrum changed accordingly.With the temperature rising from 340 K to 360 K,the variation of the transmission spectrum is recorded particularly.And the reason for the variation is analyzed carefully.At a proper temperature and magnetic field,a transmission spectrum narrowed to ~220 MHz is obtained,and the peak transmission is about 48%.The performance of the87Rb D1 line is better than that of the 85Rb.To obtain the weak signal light detection from the high background noise,a study on ultra-narrow bandwidth Faraday anomalous dispersion optical filter(FADOF) at the 87Rb D1 line,5S1/2F=2→5P1/2 F′=1transmission(795 nm) is demonstrated experimentally.A sample cell filled with Rubidium atoms in which the proportion of 87Rb is greater than that of the nature rubidium is placed in a homogeneous magnetic field between two crossed Glan-Thompson polarizers.The incident probe light goes through the sample cell,and interacts with the atoms.Because of the Faraday rotation,the function of the filter can be realized.When the experiment condition changed,the result of transmission spectrum changed accordingly.With the temperature rising from 340 K to 360 K,the variation of the transmission spectrum is recorded particularly.And the reason for the variation is analyzed carefully.At a proper temperature and magnetic field,a transmission spectrum narrowed to ~220 MHz is obtained,and the peak transmission is about 48%.The performance of the87Rb D1 line is better than that of the 85Rb.

ACTA PHOTONICA SINICAJan 1, 20132 citations

Faraday anomalous dispersion optical filter at ^133Cs weak 459 nm transition

Xiaobo Xue, Duo Pan, Xiaogang Zhang +3 more

A 459 nm Faraday anomalous dispersion optical filter (FADOF) working at the side wings of the cesium 6S1/2→7P1/2 transition with weak oscillator strength is achieved. The transmittance of the higher side wing reaches 98% at a temperature of 179°C and magnetic field above 323 G. The experimental results coincide with the theoretical predictions in 1982 and 1995, which were not realized in experiments for over three decades. Due to its high transmittance, high accuracy, and narrow linewidth, the 459 nm FADOF can be applied in underwater optical communications, the building of active optical clocks, and laser frequency stabilization in active optical clocks.A 459 nm Faraday anomalous dispersion optical filter (FADOF) working at the side wings of the cesium 6S1/2→7P1/2 transition with weak oscillator strength is achieved. The transmittance of the higher side wing reaches 98% at a temperature of 179°C and magnetic field above 323 G. The experimental results coincide with the theoretical predictions in 1982 and 1995, which were not realized in experiments for over three decades. Due to its high transmittance, high accuracy, and narrow linewidth, the 459 nm FADOF can be applied in underwater optical communications, the building of active optical clocks, and laser frequency stabilization in active optical clocks.

Photonics ResearchSep 11, 201517 citations

Using laser cooling technology, we demonstrate an ultranarrow-bandwidth Faraday anomalous dispersion optical filter (FADOF) which operates on the

5^{2}\text{S}_{1/2}

(

F = 2

) to

6^{2}\text{P}_{3/2}

(

F' = 3

) transition at 420 nm based on cold 87Rb atoms. The filter achieves a single 2.7(2) MHz passband at a peak transmission of 3.2%. It is the narrowest bandwidth FADOF known at present, as the influence of Doppler broadening on the bandwidth narrowing of FADOF is effectively overcome by cold atoms. This ultranarrow-bandwidth FADOF has a figure of merit (FOM) value of 11.85 GHz−1, which is seven times larger than the largest FOM achieved by thermal vapor atomic optical filter published to date. Furthermore, the scheme can be extended to almost all kinds of atomic optical filters and may find applications in active Faraday optical frequency standard and self-stabilizing laser.