Orbital angular momentum of an astigmatic Hermite-Gaussian beam
An explicit formula for the normalized orbital angular momentum (OAM) of an elliptical Hermite-Gaussian (HG) beam of orders (0, n) focused by a cylindrical lens is obtained. In modulus, this OAM can be both greater and smaller than n. If the cylindrical lens focuses not an elliptical, but a conventi...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Samara National Research University
2018-02-01
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| Series: | Компьютерная оптика |
| Subjects: | |
| Online Access: | http://computeroptics.smr.ru/KO/PDF/KO42-1/420102.pdf |
| Summary: | An explicit formula for the normalized orbital angular momentum (OAM) of an elliptical Hermite-Gaussian (HG) beam of orders (0, n) focused by a cylindrical lens is obtained. In modulus, this OAM can be both greater and smaller than n. If the cylindrical lens focuses not an elliptical, but a conventional HG beam, the latter will also have an OAM that can be both larger and smaller in modulus than that of an elliptical HG beam. For n = 0, this beam converts to an astigmatic Gaussian beam, but, as before, it will still have OAM. With the help of two interferograms, a phase of the astigmatic Gaussian beam is reconstructed, which is then used to calculate the normalized OAM. The values of the OAM calculated by the theoretical formula and using a hybrid method combining modeling with experiment differ only by 6 %. |
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| ISSN: | 0134-2452 2412-6179 |