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Abstract This paper proposes an alternative mechanism to solve the so-called missing pulsar problem, a standing paradox between the theoretical expectations about the number of pulsars that should exist in the galaxy center of the Milky Way and their absence in the observations. The mechanism is based on the transformation of incident$$\gamma $$ rays into hybridized modes, known as axion-polaritons, which can exist inside highly magnetized quark stars with a quark matter phase known as the magnetic dual chiral density wave phase. This phase, which is favored over several other dense matter phases candidates at densities a few times nuclear saturation density, has already passed several important astrophysical tests. In the proposed mechanism, the absence of young magnetars occurs because as electromagnetic waves inside the star can only propagate through the hybridized modes, incident photons coming from a$$\gamma $$ -ray burst get transformed into massless and massive axion polaritons by the Primakoff effect. Once thermalized, the massive axion-polaritons can self-gravitate up to a situation where their total mass overpasses the Chandrasekhar limit for these bosons, producing a mini blackhole that collapses the star.
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This content will become publicly available on December 1, 2026
Binary phase-only gallium oxide diffractive optical element for beam shaping
Abstract This study presents an experimentally validated demonstration of an inverse-optimized binary phase-only gallium oxide diffractive optical element (DOE). This DOE transforms an incident Gaussian beam into a square flat-top beam at the working plane. The design methodology for this binary phase-only DOE beam shaper is founded on an efficient process that integrates the modified Gerchberg-Saxton algorithm and the adjoint method. Experimental characterization of the fabricated device on a single crystal$$(\overline{2} \; 01)$$gallium oxide substrate is conducted at a wavelength of 532 nm, confirming its ability to transform an incident Gaussian beam into a focused square flat-top beam. Such a device holds significant promise for various high-power laser applications, notably in laser welding and similar domains. Furthermore, because of the ultrawide bandgap of gallium oxide, DOEs operating at shorter wavelengths in the UV are also possible based on this technique.
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- Award ID(s):
- 2234413
- PAR ID:
- 10600843
- Publisher / Repository:
- Nature
- Date Published:
- Journal Name:
- Scientific Reports
- Volume:
- 15
- Issue:
- 1
- ISSN:
- 2045-2322
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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