Plasmo-thermomechanical radiation detector with on-chip optical readout

Abstract

Plasmonic structures have long proved their capabilities to concentrate and manipulate light in micro-and nano-scales that facilitate strong light-matter interactions. Besides electromagnetic properties, ultra-small plasmonic structures may lead to novel applications based on their mechanical properties. Here we report efficient coupling between optical absorption and mechanical deformation in nanoscales through plasmonically enhanced fishbone nanowires. Using tailorable absorbers, free-space radiation energy is converted into heat to thermally actuate the suspended nanowires whose deformation is sensed by the evanescent fields from a waveguide. The demonstration at 660 nm wavelength with above 30% absorption shows the potential of the device to detect nW/√Hz power in an uncooled environment. IntroductionThe fundamental mechanism of infrared detection is energy transduction from the electromagnetic domain to others. Depending on the energy transduction mechanism, most of the infrared detectors can be classified as either photon detection or thermal sensing [1]. The semiconductor-based photonic detectors [2][3][4] have the advantages of high signal-to-noise ratio and fast response time. However, these advantages come at the expense of bulkiness, high cost, and power-inefficiency due to the use of cryogenic cooling. On the other hand, thermal detectors that utilize the temperature-induced changes in material properties are less expensive, more power efficient, and compatible with room temperature operations. Up to date, several uncooled thermal detectors have been demonstrated based on pyroelectricity [5][6][7], thermoelectricity [8][9][10], conductivity [11][12][13][14], piezoelectricity [15], optical resonance [16], mechanical deflection [17,18], etc. Thermo-mechanical detectors rely on the structural deformation upon exposure to radiation. As structure sizes go into nanoscales, finding an efficient light concentrator that can generate enough temperature gradient in subwavelength dimensions becomes one of the fundamental challenges. Fortunately, the plasmonic structures address this challenge by enhancing the light-matter interaction and boosting the absorption [19,20] in nanoscales. Another challenge lies in converting the tiny mechanical deflection into a measurable quantity. In doing so, optical approaches often utilize trigonometry [21,22] and interferometry [23,24] to amplify the displacement. However, these optical systems require discrete bulky lenses and detectors, hence they are difficult to miniaturize. Therefore, it is highly desirable to have efficient actuation in plasmonic nanomechanical structures with compact and sensitive on-chip transduction [25-27] and on-chip optical readout.

Performance-Enhanced Polysilicon Microbolometer in CMOS Technology With a Grating Structure

“…At this time, the enhancement region of the local electric field at the interface between Al grating and SiO2 can also be observed, and the absorptivity of device A is also increased. Therefore, the main reason for the enhanced responsivity is that the generation of plasmonic structure SPPs of the Al grating absorber improves the infrared absorptivity of the absorber [32][33][34][35]. Fig.…”

Plasmomechanical Systems: Principles and Applications

“…[ 74 ] Thus, integrating plasmonic nanomaterials together with mechanical nanoresonators can lead to efficient conversion of optical energy into heat and induce, for example, mechanical deformation via photothermal effect, which is crucial for the realization of on‐chip optical readout of free‐space radiation at room temperature. [ 75,76 ] As discussed in Section 2.3, plasmonic photothermal absorbers are also important for broadband manipulation of mechanical resonances. [ 51 ] In this regard, Ou et al., have designed and experimentally demonstrated mechanically reconfigurable photonic metamaterials.…”

“…[83,96] Generally, thermomechanical detectors rely on the structural deformation upon exposure to radiation. [75] Similarly, plasmo-thermomechanical detectors exploit the thermoplasmonic effect resulting from light absorption by plasmonic nanostructures which act as nanoscale heat sources capable of inducing thermomechanical actuation. [97] In particular, Yi et al designed a plasmo-thermomechanical IR detector (Plas-MIRD) built by integrating plasmonic nanoantenna absorbers with nano-mechanical structures.…”

Direct thermal infrared vision via nanophotonic detector design

“…We note that optical measurement of thermal IR detector pixels has been explored previously in Refs. [11][12][13][14][15][16][17]. Moreover, Refs.…”

“…1(b). Our design utilizes resonant waveguide gratings [18,19] which are different in terms of both geometry and material options from all above-mentioned works [11][12][13][14][15][16][17] in the context of optical measurement of IR detectors.…”