Loss‐induced phase transition in mid‐infrared plasmonic metamaterials for ultrasensitive vibrational spectroscopy

Abstract

Metamaterials have proven their ability to possess extraordinary physical properties distinct from naturally available materials, leading to exciting sensing functionalities and applications. However, metamaterial-based sensing applications suffer from severe performance limitations due to noise interference and design constraints. Here, we propose a dual-phase strategy that leverages lossinduced different Fano-resonant phases to access both destructive and constructive signals of molecular vibration. When the two reverse signals are innovatively combined, the noise in the detection system is effectively suppressed, thereby breaking through the noise-related limitations. Additionally, by utilizing loss optimization of the plasmon-molecule coupling system, our dual-phase strategy enhances the efficiency of infrared energy transfer into the molecule without any additional fabrication complex, thereby overcoming the trade-off dilemma between performance and fabrication cost. Thanks to the pioneering breakthroughs in the limitations, our dual-phase strategy possesses an overwhelming competitive advantage in ultrasensitive vibrational spectroscopy over traditional metamaterial technology, including strong signal strength (Â4), high sensitivity (Â4.2), effective noise suppression (30%), low detection limit (13 ppm), and excellent selectivity among CO 2 , NH 3 , and CH 4 mixtures. This work not only opens the door to various emerging ultrasensitive detection applications, including ultrasensitive in-breath diagnostics and highinformation analysis of molecular information in dynamic reactions, but also Hong Zhou and Dongxiao Li contributed equally to this work.

Emerging Wearable Chemical Sensors Enabling Advanced Integrated Systems toward Personalized and Preventive Medicine

“…In parallel to demonstrating soft, flexible optical chemical sensors that can be embedded into textile structures or attached to human skin, the interest in small, robust, and sensitive sensors using different sensing mechanisms is also increasing. In the past decade, infrared plasmonic nanoantennas (PNA) have emerged as powerful tools to identify molecules by plasmon-molecule interaction. − Nevertheless, current PNAs are typically limited in bandwidth and sensitivity due to the sharp plasmonic resonance peaks and weak coupling between sensing hotspots and molecules. Recently, Ren et al proposed wavelength-multiplexed hook nanoantennas (WMHNA) as ultrasensitive vibrational probes for complex molecular recognition, with a broadband working wavelength ranging from 6 to 9 μm .…”

Machine learning-augmented surface-enhanced spectroscopy toward next-generation molecular diagnostics

“…3 SERS and SEIRA provide lattice and molecular vibrational fingerprint information, respectively, which is directly related to the molecular constituents, chemical bonds, and configuration. [4][5][6][7][8] This correlation makes them powerful analytical tools for unambiguous, nondestructive, and label-free detection of substances in biology, medicine, electrochemistry, catalysis, materials science, etc. 9 Since the intrinsic mechanisms of SEF and the other two are quite different, we will not discuss them in this review.…”

Ultrasensitive Molecular Fingerprint Retrieval Using Strongly Detuned Overcoupled Plasmonic Nanoantennas

“…According to the ratio of system radiative loss (𝛾 r ) to absorptive loss (𝛾 a ), TCMT divides PNAs into three cases: undercoupled (UC, 𝛾 r /𝛾 a <1), critically coupled (CC, 𝛾 r /𝛾 a = 1), and overcou-pled (OC, 𝛾 r /𝛾 a >1). [24] Current research on loss engineering mainly focuses on the improvement of the enhancement factor of PNAs [21,[25][26][27][28][29][30] (Note S1 and Figure S1, Supporting Information). In fact, the Q factor of PNAs with various losses is different, which inspires us to use loss engineering to improve the bandwidth of PNAs and maintain high light-matter coupling under spectral detuning.…”