Method of rotating light in a cylindrical cell

Patent metadata

Field	Value
Publication number	US-10260952-B1
Application number	US-201816152116-A
Country	US
Kind code	B1
Filing date	Oct 4, 2018
Priority date	Oct 16, 2017
Publication date	Apr 16, 2019
Grant date	Apr 16, 2019

Abstract

A Faraday rotation device includes a light source configured to transmit a light beam; a first rotation stage polarizer configured to forward the light beam from the light source at a predetermined reference polarization angle; a quartz cell configured to receive the light beam from the first rotation stage polarizer at the predetermined reference polarization angle; one or more stacked ring permanent magnets coaxially fitted around the quartz cell; a stepper motor configured to adjust a rotational motion of a second rotation stage polarizer connected to the stepper motor, wherein the second rotation stage polarizer is configured to change a polarization angle of the light beam received from the quartz cell; a light detector; and an electronic circuit board configured to record a change in angle between the predetermined reference polarization angle and the changed polarization angle.

First claim

The invention claimed is:

1. A method of recording a Faraday rotation angle, the method comprising:
transmitting a light beam from a GaN-based blue light source through a first rotation stage polarizer at a predetermined reference angle to obtain a first polarization light beam;
transmitting the first polarization light beam through a cylindrical quartz cell surrounded by one or more stacked ring permanent magnets, the cylindrical quartz cell including a first hole on a circular entrance of the cylindrical quartz cell and a second hole on a circular exit of the cylindrical quartz cell, the first hole and the second hole creating a tunnel within the cylindrical quartz cell structure and being connectable to a dry vacuum pump to evacuate air, and to flush and change a sample;
rotating, via the one or more stacked ring permanent magnets, a polarization direction of the transmitted first polarization light beam by a predetermined rotation angle;
rotating a second rotation stage polarizer, via a stepper;
receiving the first polarization light beam at the second rotation stage polarizer;
searching, via a photodetector, for a minimal signal from a second polarization light beam emitted from the second rotation stage polarizer;
halting a rotation of the stepper when the minimal signal is detected; and
recording, via an electronic circuit board, a rotation angle between the predetermined reference angle and an angle at which the rotation of the stepper halted.

2. The method of claim 1 , further comprising:
collimating, via an iris diaphragm, the light beam outputted from the light source.

3. The method of claim 1 , further comprising:
focusing, via an aspheric lens, the light beam outputted from the light source.

4. The method of claim 1 , further comprising:
producing, via the one or more stacked ring permanent magnets, a magnetic field inside the cylindrical quartz cell parallel to the transmitted light beam from the light source.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Al-Basheer Watheq
• ABDELAZEM Sohaib

Classifications

• G01J4/04 Primary

  Polarimeters using electric detection means (G01J4/02 takes precedence) · CPC title

• F21V23/003

  the elements being electronics drivers or controllers for operating the light source, e.g. for a LED array · CPC title

• F21Y2115/10

  Light-emitting diodes [LED] · CPC title