Spectroscopic assembly and method
A spectrometer assembly is provided having an optical transmission filter including a stack of continuous, non-patterned alternating dielectric and metal layers. Angle-dependent transmission wavelength shift of the optical transmission filter with continuous metal layers is small e.g. in comparison with multilayer dielectric filters, facilitating size reduction of the spectrometer assembly.
1. A sensor comprising:
a first signal filter for transmitting a first portion of a signal light at a first signal transmission wavelength, while blocking excitation light,
wherein the first signal filter includes:
a first area including first continuous, non-micro-structured metal layers and first dielectric layers stacked in alternation, and
a second area consisting of a stack of additional dielectric layers, and
wherein an angular sensitivity of the first signal transmission wavelength is less, for the first signal filter, as compared to a signal filter including micro-structured metal layers.
2. The sensor of claim 1 , further comprising:
a second signal filter for transmitting a second portion of the signal light at a second signal transmission wavelength, while blocking excitation light,
wherein the second signal filter includes second continuous, non-micro-structured metal layers and second dielectric layers stacked in alternation.
3. The sensor of claim 2 , wherein an angular sensitivity of the second signal transmission wavelength is less, for the second signal filter, as compared to the signal filter including micro-structured metal layers.
4. The sensor of claim 1 , further comprising:
a scattering filter for transmitting scattered excitation light at a scattering transmission wavelength, while blocking the signal light.
5. The sensor of claim 4 , wherein the scattering filter includes second continuous, non-micro-structured metal layers and dielectric layers stacked in alternation.
6. The sensor of claim 1 , wherein a total thickness of the first continuous, non-micro-structured metal layers and the first dielectric layers of the first signal filter is less than 5 mm.
7. The sensor of claim 1 , wherein a total thickness of the first continuous, non-micro-structured metal layers and the first dielectric layers of the first signal filter is less than 1 mm.
8. The sensor of claim 1 , wherein the first continuous, non-micro-structured metal layers are absent a pattern of features smaller than 2 mm.
9. The sensor of claim 1 ,
wherein each of the first continuous, non-micro-structured metal layers has a tapered edge at a periphery of the first signal filter, and
wherein each tapered edge is protectively covered by one or more of the first dielectric layers.
10. The sensor of claim 1 , wherein the signal light comprises a single-photon fluorescence, a multiphoton fluorescence, or an optical harmonic scattering of the excitation light.
11. The sensor of claim 1 , wherein the stack of additional dielectric layers increases attenuation of the first signal transmission wavelength.
12. The sensor of claim 1 , wherein the non-micro-structured metal layers are sized to exhibit a plasmon resonance effect.
13. A method comprising:
transmitting, using a signal filter, a portion of signal light, emitted from a sample, at a signal transmission wavelength,
wherein the signal filter includes:
a first area including continuous, non-micro-structured metal layers and dielectric layers stacked in alternation, and
a second area consisting of a stack of additional dielectric layers.
14. The method of claim 13 , wherein the stack of additional dielectric layers increases attenuation of the signal transmission wavelength.
15. The method of claim 13 , wherein the non-micro-structured metal layers do not include a pattern of features.
16. The method of claim 13 , wherein the continuous, non-micro-structured metal layers are sized to exhibit a plasmon resonance effect.
17. The method of claim 13 , wherein an angular sensitivity of the signal transmission wavelength is less, for the signal filter, as compared to another signal filter that includes micro-structured metal layers.
18. The method of claim 13 , further comprising:
collecting the portion of the signal light at a collection angle of at least 60 degrees; and
detecting an electrical signal, based on the portion of the signal light, provided by a photodetector.
19. The method of claim 18 , wherein the collection angle is at least 150 degrees.
20. A sensor comprising:
a transmission optical filter including:
a first area including continuous, non-microstructured metal layers and dielectric layers stacked in alternation, and
a second area consisting of a stack of additional dielectric layers,
wherein the transmission optical filter discriminates between an excitation wavelength and a signal wavelength, and
wherein an angular dependence of a transmission wavelength of the transmission optical filter is less than another angular dependence of another transmission wavelength of another transmission optical filter that includes micro-structured metal layers.