Spectroscopic assembly and method

• US 9,568,362 B2
• Filed: 08/28/2013
• Issued: 02/14/2017
• Est. Priority Date: 12/19/2012
• Status: Active Grant

• Current Assignee: Viavi Solutions, Inc. (Lumentum Holdings Inc.)
• Original Assignee: Viavi Solutions, Inc. (Lumentum Holdings Inc.)
• Inventors: Ockenfuss, Georg J.
• Primary Examiner(s): Won, Bumsuk
• Assistant Examiner(s): Parbadia, Balram
• Application Number:
  US14/012,855
• Publication Number:
  US 20140170765A1
• Time in Patent Office: 1,266 Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2562/0233 Special features of optical sensors or probes classified in A61B5/00
• CPC Class Codes: A61B 2562/12 Manufacturing methods specially adapted for producing sensors for in-vivo measurements
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/0071 by measuring fluorescence emission
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence
• CPC Class Codes: G01J 1/0488 with spectral filtering
• CPC Class Codes: G01J 1/42 using electric radiation detectors optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10
• CPC Class Codes: G01J 2003/1226 Interference filters
• CPC Class Codes: G01J 3/0229 using masks, aperture plates, spatial light modulators or spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 3/0256 Compact construction
• CPC Class Codes: G01J 3/4406 Fluorescence spectrometry
• CPC Class Codes: G01N 21/645 Specially adapted constructive features of fluorimeters
• CPC Class Codes: G02B 5/285 comprising deposited thin solid films G02B5/281 - G02B5/289 take precedence; multilayered film filters for fibre optic multiplexing G02B6/29361

Abstract

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.

Claims

1. A spectrometer assembly comprising:

a holder for holding a sample for emitting signal light when excited with excitation light;

a first signal filter, coupled to the holder, for transmitting a first portion of the signal light at a first signal transmission wavelength, while blocking the excitation light; and

a first photodetector, coupled to the first signal filter, for providing a first electrical signal upon illumination with the first portion of the signal light transmitted through the first signal filter,

wherein the first 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,

wherein the stack of additional dielectric layers increases attenuation of the first signal transmission wavelength,

wherein the non-micro-structured metal layers are continuous films that do not include a pattern of features that are shaped and sized to exhibit a plasmon resonance effect, 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 spectrometer assembly of claim 1, further comprising:

a second signal filter, coupled to the holder, for transmitting a second portion of the signal light at a second signal transmission wavelength, while blocking the excitation light; and

a second photodetector, coupled to the second signal filter, for providing a second electrical signal when illuminated with the second portion of the signal light transmitted through the second signal filter,

wherein the second signal filter includes continuous, non-micro-structured metal layers and dielectric layers stacked in alternation,

wherein an angular sensitivity of the second signal transmission wavelength is less, for the second signal filter, as compared to a signal filter including micro-structured metal layers.

3. The spectrometer assembly of claim 1, further comprising:

a scattering filter, coupled to the holder, for transmitting scattered excitation light at a scattering transmission wavelength, while blocking the signal light;

a photodetector, coupled to the scattering filter, for providing an electrical signal when illuminated with the scattered excitation light transmitted through the scattering filter,

wherein the scattering filter includes continuous, non-micro-structured metal layers and dielectric layers stacked in alternation,

wherein an angular sensitivity of the scattering transmission wavelength is less, for the scattering filter, as compared to a scattering filter including micro-structured metal layers.

4. The spectrometer assembly of claim 1, further comprising:

an excitation light source for emitting the excitation light; and

a first excitation filter, coupled to the excitation light source, for transmitting a first portion of the excitation light at a first excitation transmission wavelength, while blocking the signal light;

wherein the holder is coupled to the first excitation filter for receiving the first portion of the excitation light transmitted through the first excitation filter, and

wherein the first excitation filter includes continuous, non-micro-structured metal layers and dielectric layers stacked in alternation,

wherein an angular sensitivity of the first excitation transmission wavelength is less, for the first excitation filter, as compared to an excitation filter including micro-structured metal layers.

5. The spectrometer assembly of claim 4, further comprising:

a second excitation filter, coupled to the excitation light source, for transmitting a second portion of the excitation light at a second excitation transmission wavelength, while blocking the signal light;

wherein the holder is coupled to the second excitation filter for receiving the second portion of the excitation light transmitted through the second excitation filter, and

wherein the second excitation filter includes a stack of continuous, non-micro-structured metal layers and dielectric layers,

wherein an angular sensitivity of the second excitation transmission wavelength is less, for the second excitation filter, as compared to an excitation filter including micro-structured metal layers.

6. The spectrometer assembly of claim 4, wherein the first excitation filter is integral with the excitation light source.

7. The spectrometer assembly of claim 4, wherein the first signal filter and the first excitation filter are disposed on a same side of the holder.

8. The spectrometer assembly of claim 7, wherein the first signal filter and the first excitation filter are attached directly to the holder.

9. The spectrometer assembly of claim 1, wherein a total thickness of the continuous, non-micro-structured metal layers and the dielectric layers of the first signal filter is less than 5 micrometers.

10. The spectrometer assembly of claim 1, wherein a total thickness of the continuous, non-micro-structured metal layers and the dielectric layers of the first signal filter is less than 1 micrometer.

11. The spectrometer assembly of claim 1, wherein the non-micro-structured metal layers are absent a pattern of features smaller than 2 micrometers.

12. The spectrometer assembly of claim 1, wherein the non-micro-structured metal layers comprise silver or aluminum.

13. The spectrometer assembly of claim 12, wherein the dielectric layers comprise a metal oxide.

14. The spectrometer assembly of claim 13, wherein the metal oxide comprises one or more of Ta₂O₅, Nb₂O₅, or TiO₂.

15. The spectrometer assembly of claim 1, wherein

each of the non-micro-structured metal layers has a tapered edge at a periphery of the first signal filter, and

each tapered edge is protectively covered by one or more of the dielectric layers.

16. The spectrometer assembly of claim 1, wherein the first signal filter is integral with the first photodetector.

17. The spectrometer assembly of claim 1, wherein the sample includes a marker fluorophore that changes fluorescence properties upon binding to a target molecule, thereby indicating presence of the target molecule in the sample.

18. The spectrometer assembly of claim 1, wherein the signal light comprises a single-photon fluorescence, multiphoton fluorescence, or an optical harmonic scattering of the excitation light.

19. A method comprising:

illuminating a sample with excitation light;

transmitting, using a signal filter, a portion of signal light, emitted from the 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,

wherein the stack of additional dielectric layers increases attenuation of the signal transmission wavelength,

wherein the non-micro-structured metal layers are continuous films that do not include a pattern of features that are shaped and sized to exhibit a plasmon resonance effect, and

wherein an angular sensitivity of the signal transmission wavelength is less, for the signal filter, as compared to a signal filter including micro-structured metal layers;

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.

20. The method of claim 19, wherein the collection angle is at least 150 degrees.

21. An optical spectrometer comprising:

a transmission optical filter including 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,

wherein the stack of additional dielectric layers increases wavelength attenuation,

wherein the transmission optical filter discriminates between an excitation wavelength and a signal wavelength,

wherein the non-micro-structured metal layers are continuous films that do not include a pattern of features that are shaped and sized to exhibit a plasmon resonance effect, and

wherein an angular dependence of a transmission wavelength of the transmission optical filter is less than an angular dependence of a transmission wavelength of a transmission optical filter including micro-structured metal layers, thereby lessening a size of the optical spectrometer.

22. The optical spectrometer of claim 21, wherein the dielectric layers comprise one or more of Ta₂O₅, Nb₂O₅, or TiO₂.