Dual sensitization enhancement in cavity optomechanics for ultra-high resolution temperature sensing

As a basic physical parameter, temperature plays an important role in science and industry areas. The cavity optomechanics especially the spring effect provide an ideal platform for precision measurement. Here, we bridge between optical sensitization and optomechanical transduction by fabricating a liquid-core microbubble resonator to realize dual sensitization enhancement. The high thermo-optic coefficient liquid is injected into the microbubble to increase the temperature sensitivity of optical resonant peak shift. The optomechanical spring effect is used to transduce the amplified optical shift to mechanical frequency change and further enhance the temperature response. Through the enhancement combination of optical and mechanical methods, we have achieved a sensitivity of 8.1 MHz/°C, which is at least two orders of magnitude higher than traditional optomechanical approaches. The temperature resolution is estimated as high as 5.3×10 ^-5 °C with mechanical frequency linewidth 8.6 kHz. A capillary ethanol evaporation experiment is constructed to demonstrate capability of the tiny temperature fluctuations measurement. The novel dual approach greatly enhanced the ultra-high resolution sensing capability and have a flexible sensitivity adjust potential with simply injecting different liquids.