Erbium fiber laser-based direct frequency comb spectroscopy of Rb two-photon transitions

Abstract

We demonstrate the direct frequency comb spectroscopy of Rb 5S→5D two-photon transitions directly excited by an optical frequency comb (OFC) in 1.5 μm fiber communication bands. A chain of comb spectral manipulation and quantum coherence control is implemented to enhance the efficiency of second harmonic OFC generation and eliminate the Doppler-broadening background. The direct frequency comb spectroscopy with clearly resolved transition lines is obtained. Our scheme provides a potential approach to realize the OFC at ~1.5 μm with high stability and accuracy.

The Optimization of Cold Rubidium Atom Two-Photon Transition Excitation with an Erbium-Fiber Optical Frequency Comb

“…With the development of frequency-stabilization techniques [1][2][3] and laser cooling and trapping techniques [4], two-photon spectroscopy has developed fast in recent years. For its high accuracy and stability, two-photon spectroscopy has many practical applications in many fields, such as fiber communication [5,6], precision measurement [7][8][9][10][11][12][13][14][15], detection of macromolecules [16], and Doppler laser cooling [17,18]. Among this, the Rubidium (Rb) 5S 1/2 -5D 5/2 two-photon transition (TPT) has unique advantages, such as narrow linewidth and low sensitivity to environment [19].…”

“…The stability of the Rb two-photon frequency standard has reached 10 −13 [20]. Because of many natural advantages of optical frequency comb (compact scheme, wide spectrum bandwidth and high peak intensity), the direct frequency comb spectroscopy (DFCS) on the TPTs is the research focus of two-photon spectroscopy [5][6][7][8][9][10][11][12][13][14][15]. Compared to a narrow-linewidth continuous wave (CW) laser, the linewidth of each optical comb teeth is easier to be realized and adjusted to sub-hertz [21].…”

“…In addition, a coherent control method, which uses optical frequency comb to directly excite TPT, was proposed in recent years [8]. This method, which is called Direct Frequency Comb Spectroscopy (DFCS), is widely used for TPT spectroscopy of molecules and ions [5,6,[9][10][11][12][13][14][15]. In the previous work, we explore a simplified scheme to obtain the DFCS of Rb two-photon transition [5,6].…”

“…This method, which is called Direct Frequency Comb Spectroscopy (DFCS), is widely used for TPT spectroscopy of molecules and ions [5,6,[9][10][11][12][13][14][15]. In the previous work, we explore a simplified scheme to obtain the DFCS of Rb two-photon transition [5,6]. In contrast to the conventional scheme, this scheme utilizes an Erbium-fiber-based frequency comb to excite the two-photon transition.…”

A Deep Ultraviolet Mode-locked Laser Based on a Neural Network

“…For higher instantaneous powers and conversion efficiencies of the Ti:sapphire MLL, the lasers can convert IR lasers into the DUV region with nonlinear crystals. In addition, direct frequency comb spectroscopy (DFCS) [22][23][24][25][26][27] with mode-locked lasers can extend spectroscopy into the DUV region.…”