Electronic structure and unconventional nonlinear response in double Weyl semimetal <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>Sr</mml:mi><mml:msub><mml:mi>Si</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>

Considering a non-centrosymmetric, non-magnetic double Weyl semimetal (WSM) SrSi$_2$, we investigate the electron and hole pockets in bulk Fermi surface behavior that enables us to characterize material as type-I WSM. We study structural handedness of correlate it with distinct at two opposite surfaces following an energy evolution. The arc singlet becomes doublet onset spin orbit coupling is accordance topological charge Nodes (WNs). A finite separation between WNs chirality SrSi$_2$ allows compute circular photogalvanic effect (CPGE). Followed by three band formula, show CPGE only quantized for level chosen vicinity WN residing higher value energy. Surprisingly, other lower energy, not found be quantized. Such complete contrast time reversal breaking WSM where plateau depending on activated WN. further analyze our finding examining momentum resolved CPGE. Finally formula able capture quantization apprehended formula.