Multi-purpose optical head probe

• US 5,381,237 A
• Filed: 08/18/1993
• Issued: 01/10/1995
• Est. Priority Date: 08/18/1993
• Status: Expired due to Fees

• Current Assignee: Petrometrix, Ltd.
• Original Assignee: Petrometrix, Ltd.
• Inventors: Sela, Ilan
• Primary Examiner(s): EVANS, FANNIE L
• Application Number:
  US08/107,871
• Time in Patent Office: 510 Days
• Field of Search: 385/12, 128/634, 128/665, 250/458.1, 250/459.1, 250/461.1, 250/461.2, 250/227.23, 250/227.24, 250/227.28, 356/128, 356/133, 356/432, 356/436, 356/440, 356/301, 356/317, 356/318, 356/446
• US Class Current: 356/436
• CPC Class Codes: G01N 21/255 Details, e.g. use of specially adapted sources, lighting or optical systems
• CPC Class Codes: G01N 21/359 using near infrared light
• CPC Class Codes: G01N 21/431 Dip refractometers, e.g. using optical fibres
• CPC Class Codes: G01N 21/65 Raman scattering
• CPC Class Codes: G01N 21/8507 Probe photometers, i.e. with optical measuring part dipped into fluid sample
• CPC Class Codes: G01N 2201/08 Optical fibres; light guides

Abstract

An optical probe head for determining the index of refraction of a sample, which is made up of a gradient index lens in contact with the sample, a transmitting optical fiber for inputting radiation into said gradient index lens and a receiving optical fiber. The optical fibers and gradient index lens are aligned so that radiation from the transmitting optical fiber which is reflected from the interface of the gradient index lens and the sample is received by the receiving optical fiber. The probe can, with slight changes, also be used for determining the Raman or fluorescent spectra, for determining the absorption spectrum, and for determining the self-referencing transmission of a sample.

Claims

1. An optical probe head for determining the absolute transmission or absorption of a sample, comprising:

(a) a gradient index lens;

(b) a mirror placed so as to reflect radiation coming through said gradient index lens back to said gradient index lens through the sample;

(c) a moveable partition located between said gradient index lens and said mirror, said partition serving to alternately block and unblock radiation between said mirror and said gradient index lens;

(d) at least one transmitting optical fiber for inputting radiation into said gradient index lens;

(e) at least one receiving optical fiber, said at least one transmitting optical fiber and said at least one receiving optical fiber being fixedly held relative to said gradient index lens so that said gradient index lens and said optical fibers are aligned such that radiation input into said gradient index lens by said transmitting optical fiber which passes through said gradient index lens and the sample to said mirror is reflected by said mirror through the sample and through said gradient index lens and is received by said at least one receiving optical fiber when said moveable partition is not blocking radiation between said mirror and said gradient index lens and such that, when said moveable partition is blocking radiation between said mirror and said gradient index lens. Radiation input into said gradient index lens by said transmitting optical fiber is reflected from an interface of said gradient index lens and air and is received by said at least one receiving optical fiber.

2. A probe head as in claim 1, wherein said at least one transmitting optical fiber and said at least one receiving optical fibers are held in a ferrule which is connected to said gradient index lens.

3. A probe head as in claim 11, wherein said aligning of said optical fibers and said gradient index lens is effected by introducing radiation through one of said optical fibers, moving said optical fibers and said gradient index lens relative to each other until maximum radiation intensity is detected in the other of said optical fibers and fixing the position of said optical fibers and said gradient index.