Zhou Xuewen, Gather Malte C, Scarcelli Giuliano
Fischell Department of Bioengineering, University of Maryland, College Park, Maryland 20742, United States.
Humboldt Centre for Nano- and Biophotonics, Department of Chemistry, University of Cologne, Greinstrasse 4-6, 50939 Köln, Germany.
ACS Photonics. 2023 Dec 27;11(1):267-275. doi: 10.1021/acsphotonics.3c01448. eCollection 2024 Jan 17.
Microlasers have been widely used in biosensing applications because of their high sensitivity to changes in local conditions. However, in most applications, the sensitivity limit is not dictated by the microlaser line width but rather by the much worse spectral resolution of the detection system, typically a grating spectrometer. To address this issue, we built and characterized a two-dimensional (2D) dispersion spectrometer with a virtually imaged phase array etalon and a diffraction grating. The spectrometer can analyze microlaser emission with a spectral resolution of better than 0.300 pm, which enables high-precision measurements of spectral shifts in laser peak emission wavelength and sufficient resolution to detect changes in peak line width. Using commercial fluorescent microspheres as the microlasers, the 2D dispersion spectrometer demonstrated a detection limit for the refractive index change of a liquid medium of 1.37 × 10 RIU and a detection limit for absorption changes of less than 0.02 cm.
由于微激光器对局部条件变化具有高灵敏度，因此已被广泛应用于生物传感领域。然而，在大多数应用中，灵敏度极限并非由微激光线宽决定，而是由检测系统（通常是光栅光谱仪）差得多的光谱分辨率所决定。为了解决这个问题，我们构建并表征了一种二维（2D）色散光谱仪，它采用了虚拟成像相位阵列标准具和衍射光栅。该光谱仪能够以优于0.300皮米的光谱分辨率分析微激光发射，这使得能够对激光峰值发射波长的光谱位移进行高精度测量，并具有足够的分辨率来检测峰值线宽的变化。使用商用荧光微球作为微激光器，二维色散光谱仪展示了对液体介质折射率变化的检测限为1.37×10 RIU，对吸收变化的检测限小于0.02厘米。
