Facile fabrication of microstructured surface using laser speckle for high-sensitivity capacitive pressure sensors

The design of a maskless exposure system for fabricating the microstructured surface based on the grainy light illumination generated by laser speckle is reported. Upon combining with soft lithography, we obtained microstructured polydimethylsiloxane electrodes with microstructure sizes of 20 μm and 40 μm and microstructure fill factors ranging from 10% to 90%. The feasibility of using this method in fabricating high-sensitivity capacitive pressure sensors was demonstrated. The sensor shows the highest sensitivity of 2.14 k Pa-1under 0–100 Pa pressures, the low detection limit of 4.9 Pa, and the excellent stability and durability of 10000 cycles. The method of employing laser speckle in fabricating microstructures with different morphologies is simple and robust, which is superior to other methods such as traditional photolithography.

Research on ultracold cesium molecule long-range states by high-resolution photoassociative spectroscopy

In this paper, an ultra-high resolution photoassociation spectroscopy study on photoassociation of cesium atoms is reported. The cold cesium gas in the mag-neto-optical trap is illuminated by a photoassociation laser with red-tuning as large as 40 cm?1 below the 6S1/2 + 6P3/2 dissociation limit, and the photoassociation to the excited state ultracold molecule is detected. High signal-to-noise ratio is obtained by using the lock-in detection of the fluorescence from the modulated cold Cs at-oms. The 0g?, 1g and 0u+ long-range states which correspond to 6S1/2 + 6P3/2 dissocia-tion limit are present in the photoassociation spectrum. The effective coefficients of leading long-range interactions and the corresponding vibrational quantum num-ber are obtained using LeRoy-Bernstein Law. It is found that photoassociation process creates rotating molecules and the high J value is a hint that higher partial waves participate in the PA process in the presence of trapping laser.

Effective Slowing and Trapping of Cs Atoms in an Ultrahigh-Vacuum Apparatus

We report the effective slowing and trapping of Cs atoms in an ultrahigh-vacuum apparatus.The heated Cs atoms in an oven are slowed using a Zeeman slower after the oven chamber and then trapped using a magneto-optical trap in a science chamber.Compared to the traditional vacuum pressure of~10^(−7)Pa determined by the vapor pressure of Cs atoms in the oven chamber,the designed cold nipple and differential pumping tube are used between the oven and the oven chamber to achieve a lower vacuum pressure of~3.6×10^(−9)Pa.This is beneficial for achieving and maintaining an ultrahigh vacuum in the science chamber.We demonstrate the performance of our apparatus through the effective slowing of Cs atoms and an optimal magneto-optical trap.