Sensors using optical RF oscillators

• US 9,541,528 B2
• Filed: 03/14/2014
• Issued: 01/10/2017
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: UNM Rainforest Innovations (f/k/a STC.UNM) (The University of New Mexico)
• Original Assignee: UNM Rainforest Innovations (f/k/a STC.UNM) (The University of New Mexico)
• Inventors: Hossein-Zadeh, Mani
• Primary Examiner(s): Martin, Laura
• Assistant Examiner(s): NATH, SUMAN KUMAR
• Application Number:
  US14/213,858
• Publication Number:
  US 20140290370A1
• Time in Patent Office: 1,033 Days
• Field of Search: 736/43, 73655-657, 73/240.1, 73/240.2, 250339-343
• US Class Current: 1/1
• CPC Class Codes: G01N 21/7746 the waveguide coupled to a cavity resonator
• CPC Class Codes: G01N 2291/014 Resonance or resonant frequency
• CPC Class Codes: G01N 2291/0256 Adsorption, desorption, surface mass change, e.g. on biosensors
• CPC Class Codes: G01N 29/036 by measuring frequency or resonance of acoustic waves
• CPC Class Codes: G01N 29/2418 using optoacoustic interaction with the material, e.g. laser radiation, photoacoustics photoacoustic cells G01N21/1702; measuring characteristics of vibrations by using radiation-sensitive means G01H9/00; acousto-optical conversion techniques for short-range imaging G01S15/8965; sound-producing devices using laser bundle G10K15/046
• CPC Class Codes: G02B 6/29338 Loop resonators

Abstract

An optical microresonator based RF oscillator sensor for measuring mass, temperature, and particle/molecule concentration. An optical energy source is coupled to the optical microresonator to generate optical power oscillations at Rf frequencies. A stable or reference RF oscillation frequency is established which allows for measuring oscillation frequency variations induced by the interaction of the substance with the optical microresonator.

Claims

1. A method of using an optical microresonator based RF oscillator as a sensor comprising the following steps:

generating optical power oscillations at RF frequencies by coupling an optical energy source to said optical microresonator;

establishing a stable RF oscillation frequency; and

optionally measuring the RF oscillation frequency variation induced by a substance to be measured as said substance interacts with said optical microresonator.

2. The method of claim 1 wherein said RF oscillation frequency is monitored by converting optical power oscillations to an electronic signal by a photodetector.

3. The method of claim 2 wherein said electronic signal is measured by a frequency counter.

4. The method of claim 2 wherein said electronic signal is measured by an RF spectrum analyzer.

5. The method of claim 2 wherein said electronic signal is measured by an RF spectrum analyzer and a frequency counter.

6. The method of claim 1 wherein said optical microresonator is an optomechanical oscillator.

7. The method of claim 1 wherein said optical microresonator is a thermo-optical oscillator.

8. The method of claim 1 wherein said optical microresonator is a thermo-optomechanical oscillator.

9. The method of claim 1 wherein said optical microresonator is an optoelectronic oscillator.

10. A method of using a radiation pressure driven optomechanical RF oscillator as a mass sensor comprising the following steps:

generating optical RF power oscillations by coupling an optical energy source to said optomechanical microresonator, said oscillations are created by said radiation pressure;

establishing a stable RF oscillation frequency; and

optically measuring the RF oscillation frequency variation induced by added mass on the optomechanical microresonator.

11. The method of claim 10 wherein said RF oscillation frequency includes a fundamental frequency and harmonic frequencies.

12. The method of claim 11 wherein said harmonic frequencies are used to measure the variation induced by added mass on the optomechanical microresonator.

13. The method of claim 10 wherein an electronic signal is measured by a frequency counter.

14. The method of claim 10 wherein an electronic signal is measured by an RF spectrum analyzer.

15. The method of claim 10 wherein an electronic signal is measured by an RF spectrum analyzer and a frequency counter.

16. A method of using an optical microresonator based RF oscillator having an evanescent field as a molecule concentration sensor comprising the following steps:

generating optical power oscillations at RF frequencies by coupling an optical energy source to said optical microresonator;

establishing a stable RF oscillation frequency; and

optically measuring the RF oscillation frequency variation induced by the molecules to be measured as said molecules interact with said evanescent field of said optical microresonator.