Mechanical vibration spectrum of the microcavity membrane with the first three modes and their simulated displacements at (a) room temperature and (b) and (c) at cryogenic temperatures acquired using lock-in detection. 

Contexts in source publication

Context 1

... find the resonance frequencies of the membrane, we first perform a frequency scan at room temperature [ Fig. 3(a)]. A resonance is observed by the vibration-probe whenever the modulation frequency of the vibration-pump laser coincides with a mechanical resonance of the mem- brane. Vibration is induced by the photothermal effect. 24 The highest vibration frequency that can be excited in the microcavity is f max ¼ 1=s ¼ 4pD=r 2 ' 1:5 GHz, where s is the relaxation time, D ¼ 3:1 Â 10 À3 m 2 =s is the thermal dif- fusivity of GaAs, and r ¼ 5 Â 10 À6 m is the radius of the vibration-pump spot. While the mechanical quality-factor of the resonator at room temperature is low ( Fig. ...

Context 2

... C n is proportional to the maximal mechanical oscilla- tion amplitude, n is the mode number, J n (I n ) is the (modi- fied) Bessel function, a ¼ 350 lm is the plate radius, q is the mass density of the membrane (4450 kg/m 3 ), D ¼ Eh 3 =½12 1 ð À 2 ފ is the flexural rigidity, with Young's modulus of the (100) plane along the [110] direction E ¼ 80 GPa; 26 and with Poisson ratio ¼ 0:3. Using these values gives f 0 ¼ x 0 =2p ¼ 136 kHz (and k 0 a ¼ 3.2) which is larger than the measured 104 kHz. This discrepancy suggests that there is some radial tension in the membrane. The calculated dis- placement patterns of the first two modes (W 0;1 ) are plotted in Fig. 3(a). The radial strain for the fundamental mode [ Fig. 4(a)] ...