Photoassociation (PA) spectroscopy fre bound PA: K+ rb+ hvA >KRb (V, S+P Decay KRb→KRb+hv PA PA Group I i2, Na2, K2, Rb2, CS2, RbCs, NaCs, KRb, LiCS S+S (cold) up ll Sr2, Ca2, Yb, SrYb Internuclear distance(R) Group I+ Group ll LiB RbBb 2/3/2021 11
2/3/2021 11 Photoassociation (PA) spectroscopy S+P S+S E n erg y Internuclear distance (R) PA (cold) PA: K + Rb + hPA KRb*(v, J) Decay: KRb* KRb + h PA: Group I: Li2 , Na2 , K2 , Rb2 , Cs2 , RbCs, NaCs, KRb, LiCs, Group II: Sr2 , Ca2 , Yb2, SrYb free bound Group I + Group II: LiYb, RbYb
Photoassociation (PA) spectroscopy TOLUME 58. NUMBER 23 PHYSICAL REVIEW LETTERS 8 JUNE 1987 Laser-Induced Photoassociation of Ultracold Sodium Atoms H. R. Thorsheim and J, Weiner Department of Chemistry. Unirersity of Maryland, College Park, Maryland 20742 Molecular Spectroscopy Dicision. ards, Gaithersburg. Maryland 20899 Paul Julienne. NIST. USA We present the theory of laser-induced radiative association in terms of m and apply this theory to the specific case of Na-atom collisions at a temperature of 10 mk. Use of s permits a new kind o highresolution fre 1g 1041051061071081091 然删科的的 42s1/2+42P3/2 J Mol. Spec Stwalley 1999 !1」1L⊥⊥⊥⊥⊥⊥⊥L 13028.08 13031,08 13034.08 13037,08 13040,08 13043.0 Laser frequency(cm-1) 1. Measurement of molecular binding energy, long-range coefficient C 2. Precise study of atomic collisions: scattering length, 3. Modify collisions: optical Feshbach resonance 2/3/2021
2/3/2021 12 Photoassociation (PA) spectroscopy J. Mol. Spec. Stwalley 1999 1. Measurement of molecular binding energy, long-range coefficient Cn 2. Precise study of atomic collisions: scattering length, 3. Modify collisions: optical Feshbach resonance Paul Julienne, NIST, USA
Photoassociation experiment K and rb MOT Beams One or two species mot+ one Cw pa laser CCD ~600nm camera 1.5mJ More sensitive ion detection y gated time-of-flight mass spectroscopy Channeltron PA -1900V (~400mW 2/3/2021
2/3/2021 13 Photoassociation experiment Channeltron PA @ -1900V (~400mW) ~600nm 1.5mJ K and Rb MOT Beams CCD camera One or two species MOT + one CW PA laser More sensitive ion detection by gated time-of-flight mass spectroscopy
Two color PA: ground state potential 3,3;6)||1 Loss of trap loss (2,3;5) 1>3 TsaL PRL. 1997 (2,3;4) (2,2;4) 0.9 4+4 4 +3 0 10015.020.0 Laser Frequency Difference rotational levels (V2-V1)(GHz) 0,2,4 internuclear distance Lisdat et al.. 2002 1. Determine ground-state potential 2. Calculate scattering length from potential Loss of ground-state molecule Unpublished 1256990 12569.94 2/3/2021
2/3/2021 14 Two color PA: ground state potential Lisdat et al., 2002. “Loss of trap loss” Tsai, PRL, 1997 12569.90 12569.91 12569.92 12569.93 12569.94 * * * K Rb + J = 0 1 (a) 12569.90 12569.91 12569.92 12569.93 12569.94 (b) * * K Rb + PA frequency (cm -1) L * oss of ground-state molecule, Unpublished 1. Determine ground-state potential 2. Calculate scattering length from potential
Ground-state molecule formation via pa 32000 KRb Ground states can be populated by bound-bound 28000 spontaneous emission following PA The small amount of molecules can be detected with sensitive ion detection 2000 Molecular spectroscopy with the small amount of molecules =-31.57cm 1012141618 R(A) va112 ta 114 116118120122124126 42s2+42P3 TOF(uS) J Mol Spec Fragmentation spectrum Stwalley 1999 13041.1 Laser frequency(cm") 2/3/2021 15
2/3/2021 15 Ground-state molecule formation via PA Ground states can be populated by bound-bound spontaneous emission following PA. The small amount of molecules can be detected with sensitive ion detection. Molecular spectroscopy with the small amount of molecules 1 2 3 PA=-31.57 cm -1 Ion Signal (a.u.) TOF(S) KRb + Rb + K + Rb2+ 2 4 6 8 10 12 14 16 18 -4000 0 4000 8000 12000 16000 28000 32000 SE K(4S)+ Rb(4D) K(4S1/2)+ Rb(5S1/2) K(4S1/2)+ Rb(5PJ) E(cm -1) R(Å) X 1 + a 3 + PA 1 3 2 1 + 2 3 + 1 1 4 1 + KRb ++e - J. Mol. Spec. Stwalley 1999