Abstract: Embodiments of this application disclose a trans-impedance amplifier and a trans-impedance amplifier control method that are used in the field of circuit technologies. A trans-impedance amplifier TIA includes an inverting amplification circuit and a voltage clamping circuit. The inverting amplification circuit is connected in parallel to the voltage clamping circuit. The inverting amplification circuit includes a first PMOS transistor and a first NMOS transistor that have a common gate. A source of the first PMOS transistor is connected to a drain of the first NMOS transistor. The voltage clamping circuit includes a second PMOS transistor and a second NMOS transistor that have a common gate. Gates of the two transistors are connected to an input end of the TIA. A source of the second NMOS transistor and a drain of the second PMOS transistor are connected to an output end of the TIA.

Abstract: Various embodiments disclosed relate to a substrate. The present disclosure provides a substrate for use in both surface enhanced Raman spectroscopy and surface enhanced infrared spectroscopy. The substrate includes a flexible polymeric membrane, a plurality of metal oxide nanoparticles disposed on the polymeric membrane, and a plurality of metallic nanoparticles directly disposed on a portion of the plurality of metal oxide nanoparticles. The plurality of metal oxide nanoparticles are configured to work synergistically with metal nanoparticles upon exposure of the substrate surface to at least one of visible light or infrared radiation.

Abstract: Various embodiments disclosed relate to a substrate. The present disclosure provides a substrate for use in surface enhanced spectroscopy. The substrate includes a polymeric membrane, a semi-conductive coating on the polymeric membrane, and a plurality of metallic nanoparticles on the semi-conducive coating.

Abstract: The light-emitting device includes a light source and a gradient index (GRIN) element. The GRIN element has a cylindrical refractive index profile in which the refractive index varies radially and is substantially constant axially. The GRIN element includes a first end surface opposite a second end surface and is characterized by a length-to-pitch ratio. The GRIN element is arranged with the first end surface adjacent the light source to receive light from the light source, and emits the light from the second end surface in a radiation pattern dependent on the length-to-pitch ratio. Since the radiation pattern depends on the length-to-pitch ratio of the GRIN element, LEDs with different radiation patterns can be made simply by using GRIN elements of appropriate lengths.