Precise measurement of the line width of the photoassociation spectra of ultracold molecules by using a frequency shifter

Abstract

We propose a technique to precisely measure the line width of the photoassociation spectra of the excited cesium molecule by using a frequency shifter to generate two laser beams with a precise frequency difference. A series of photoassociation (PA) spectra are recorded with two laser beam induced molecular lines, whose peak separation serves as an accurate frequency ruler to measure the line width of the PA spectra. The full width half maximum line width was studied as a function of PA laser intensity. The extrapolated value at zero laser intensity is (34.84 ± 0.22) MHz. By analyzing other broadening mechanisms, a value of (32.02 ± 0.70) MHz was deduced. It is shown that this scheme is inexpensive, simple, robust, and is promising for applications in a variety of other atomic species.

Reanalysis of the photoassociation spectrum of133Cs2(6P3/2) 1gstate

“…[12] even reaches ∼10%. However, our result, deduced by using the S-LRB formula (8) to fit the reexamined spectral data, improves 1.27% compared with the value given in Ref. [13], at the same time the result obtained by using the S-LRB formula (8) to fit improves 0.2% compared with the value by using the F-LRB formula (6).…”

“…The value of the effective coefficient c 3 could be deduced from the fitting parameter E 3 . The values of c 3 for the (6S 1/2 + 6P 3/2 )1 g state of Cs 2 have been found to be 16.568 (8) and 16.600(2) respectively by using the F-LRB and the S-LRB formulae. For comparison, we list other theoretical and experimental fitting values of c 3 for the long-range 1 g state of Cs 2 in Table 1.…”

“…Hereafter we regard Eqs. ( 6) and (8) as the first improved LRB (F-LRB) formula as shown in Ref. [16], including only one linear term of energy, and the second improved LRB (S-LRB) formula as given in Ref.…”

“…( 6) and ( 8) and demonstrate the importance of the S-LRB formula in Eq. (8). Figure 4(a) shows nonlinear fittings by using the F-LRB formula in Eq.…”

“…The binding energy of molecular vibrational levels obtained from PAS is essential data for determining the molecular parameters and potential curves, thereby exploring long-range dipole-dipole interaction and scattering properties. [6][7][8] For cesium molecules, the reported experimental and theoretical studies have mainly focused on the long-range molecular state 0 − g with a special double potential well structure, which is helpful for effectively forming the ground state molecules during the photoassociation of ultracold atoms. [6,[9][10][11] So far, only few studies have been made of the 1 g state.…”