| 摘要 |
It is an object to provide a small-sized optical isolator that is suitable as an optical isolator used in a semiconductor laser used in applications such as medical treatment or optical measurement The optical isolator for a wavelength band of 320 to 633 nm of the present invention comprises a Faraday device having a Verdet constant at a wavelength of 405 nm of at least 0.70 min/(Oe·cm), and a first hollow magnet disposed on the outer periphery of the Faraday device and second and third hollow magnet units disposed so as to sandwich the first hollow magnet on the optical axis, the second and third hollow magnet units comprising 2 or more magnets equally divided in a direction of 90 degrees relative to the optical axis, the Faraday device having applied thereto a magnetic flux density B (Oe) within the range of Expression (1) below, and a sample length L (cm) on which the Faraday device is disposed being within the range of Expression (2) below. 0.8 × 10 4 ‰¤ B ‰¤ 1.5 × 10 4 0.25 ‰¤ L ‰¤ 0.45 |
