Exploring vacuum birefringence based on a 100 PW laser and an x-ray free electron laser beam. (8th February 2018)

• Record Type: Journal Article
• Authors: Shen, Baifei; Bu, Zhigang; Xu, Jiancai; Xu, Tongjun; Ji, Liangliang; Li, Ruxin; Xu, Zhizhan
• Is Part Of: Plasma physics and controlled fusion. Volume 60:Number 4(2018:Apr.)
• Publication Date: 2018-02-08
• Subjects: vacuum birefringence -- 100 PW -- XFEL -- SEL -- SCLF; Plasma (Ionized gases) -- Periodicals; Controlled fusion -- Periodicals; 530.44
• DOI: 10.1088/1361-6587/aaa7fb
• Languages: English
• ISSNs: 0741-3335

Abstract

Abstract: Exploring vacuum birefringence with the station of extreme light at Shanghai Coherent Light Facility is considered. Laser pulses of intensity beyond 10 23 W cm −2 are capable of polarizing the vacuum due to the ultra-strong electro-magnetic fields. The subtle difference of the vacuum refractive indexes along electric and magnetic fields leads to a birefringence effect for lights propagating through. The vacuum birefringence effect can now be captured by colliding a hard x-ray free electron laser (XFEL) beam with a high-power laser. The initial XFEL beam of pure linear polarization is predicated to gain a very small ellipticity after passing through the laser stimulated vacuum. Various interaction geometries are considered, showing that the estimated ellipticity lies between 1.8 × 10 −10 and 10 −9 for a 100 PW laser interacting with a 12.9 keV XFEL beam, approaching the threshold for todays' polarity detection technique. The detailed experimental set-up is designed, including the polarimeter, the focusing compound refractive lens and the optical path. When taking into account the efficiencies of the x-ray instruments, it is found that about 10 polarization-flipped x-ray photons can be detected for a single shot for our design. Considering the background noise level, accumulating runs are necessary to obtain high confident measurement.