Efficient extracavity generation of radially and azimuthally polarized beams

Abstract

We demonstrate an efficient transformation of a linearly polarized Gaussian beam to a radially or an azimuthally polarized doughnut (0,1)* Laguerre-Gaussian beam of high purity. We use a spatially variable retardation plate, composed of eight sectors of a lambda/2 retardation plate, to transform a linear polarization distribution to radial/azimuthal distribution. We transformed an Nd:YAG Gaussian beam with M(2)=1.3 to a radially and azimuthally polarized (0,1)* Laguerre-Gaussian beams with M(2)=2.5 and degree of radial/azimuthal polarization of 96-98%.

High power radial polarization conversion using photonic crystal segmented half-wave-plate

“…Theoretically, we calculated that, for this segmented half-wave-plate of 12 segments, the radial polarization purity can be as high as 99%, the calculated beam quality, M 2 , of the radial polarized beam is 2.32 and the transformation efficiency calculated from the overlap integral with a perfect radial polarized LG * 01 mode is 91%. This transformation efficiency is close to the theoretical limit of 93% of such segmental half-wave-plate conversion method [20]. In our experiment, we first used the 14 watts Yb fiber laser whose bandwidth is 2nm.…”

High power radial polarization conversion using photonic crystal segmented half-wave-plate

“…Theoretically, we calculated that, for this segmented half-wave-plate of 12 segments, the radial polarization purity can be as high as 99%, the calculated beam quality, M 2 , of the radial polarized beam is 2.32 and the transformation efficiency calculated from the overlap integral with a perfect radial polarized LG * 01 mode is 91%. This transformation efficiency is close to the theoretical limit of 93% of such segmental half-wave-plate conversion method [20]. In our experiment, we first used the 14 watts Yb fiber laser whose bandwidth is 2nm.…”

Ultrahigh-intensity optical slow-wave structure for direct laser electron acceleration

“…Two challenges remain: The generation of femtosecond, millijoule pulses of radially polarized light and the creation of a short, tightly focused electron bunch suitable for injection into our micrometer-scale structure. Efficient conversion of linearly polarized laser beams to radial polarization has been demonstrated for continuous-wave beams [36], and we are working to extend these results to femtosecond pulses. A simple, inexpensive electron injection technique is crucial to the success of electron acceleration with subterawatt lasers.…”

Birefringent device converts a standard scanning microscope into a STED microscope that also maps molecular orientation

“…Subsequently, the four segments were put together again by cementing them onto a common substrate (BK7), while observing the proper orientation of the fast axis. The orientation of the fast axes is similar to the orientation suggested in [17] for generating an azimuthally polarized beam; the only difference is the number of segments. Two devices were manufactured, one for performing STED at 647 nm (line from an argon-krypton laser) and one for STED at 592 nm (rendered by a frequency-doubled fiber laser).…”

High power radial polarization conversion using photonic crystal segmented half-wave-plate

“…Theoretically, we calculated that, for this segmented half-wave-plate of 12 segments, the radial polarization purity can be as high as 99%, the calculated beam quality, M 2 , of the radial polarized beam is 2.32 and the transformation efficiency calculated from the overlap integral with a perfect radial polarized LG * 01 mode is 91%. This transformation efficiency is close to the theoretical limit of 93% of such segmental half-wave-plate conversion method [20]. In our experiment, we first used the 14 watts Yb fiber laser whose bandwidth is 2nm.…”

Ultrahigh-intensity optical slow-wave structure for direct laser electron acceleration

“…Two challenges remain: The generation of femtosecond, millijoule pulses of radially polarized light and the creation of a short, tightly focused electron bunch suitable for injection into our micrometer-scale structure. Efficient conversion of linearly polarized laser beams to radial polarization has been demonstrated for continuous-wave beams [36], and we are working to extend these results to femtosecond pulses. A simple, inexpensive electron injection technique is crucial to the success of electron acceleration with subterawatt lasers.…”

Birefringent device converts a standard scanning microscope into a STED microscope that also maps molecular orientation

“…Subsequently, the four segments were put together again by cementing them onto a common substrate (BK7), while observing the proper orientation of the fast axis. The orientation of the fast axes is similar to the orientation suggested in [17] for generating an azimuthally polarized beam; the only difference is the number of segments. Two devices were manufactured, one for performing STED at 647 nm (line from an argon-krypton laser) and one for STED at 592 nm (rendered by a frequency-doubled fiber laser).…”

High power radial polarization conversion using photonic crystal segmented half-wave-plate

“…Theoretically, we calculated that, for this segmented half-wave-plate of 12 segments, the radial polarization purity can be as high as 99%, the calculated beam quality, M 2 , of the radial polarized beam is 2.32 and the transformation efficiency calculated from the overlap integral with a perfect radial polarized LG * 01 mode is 91%. This transformation efficiency is close to the theoretical limit of 93% of such segmental half-wave-plate conversion method [20]. In our experiment, we first used the 14 watts Yb fiber laser whose bandwidth is 2nm.…”

Ultrahigh-intensity optical slow-wave structure for direct laser electron acceleration

“…Two challenges remain: The generation of femtosecond, millijoule pulses of radially polarized light and the creation of a short, tightly focused electron bunch suitable for injection into our micrometer-scale structure. Efficient conversion of linearly polarized laser beams to radial polarization has been demonstrated for continuous-wave beams [36], and we are working to extend these results to femtosecond pulses. A simple, inexpensive electron injection technique is crucial to the success of electron acceleration with subterawatt lasers.…”

Birefringent device converts a standard scanning microscope into a STED microscope that also maps molecular orientation

“…Subsequently, the four segments were put together again by cementing them onto a common substrate (BK7), while observing the proper orientation of the fast axis. The orientation of the fast axes is similar to the orientation suggested in [17] for generating an azimuthally polarized beam; the only difference is the number of segments. Two devices were manufactured, one for performing STED at 647 nm (line from an argon-krypton laser) and one for STED at 592 nm (rendered by a frequency-doubled fiber laser).…”