No, when a photon passes through a slit and diffracts, it does not create more photons. Diffraction is a phenomenon that occurs when a wave, such as light, encounters an obstacle or a slit that is comparable in size to its wavelength. The wavefront of the light bends around the edges of the slit, causing the light to spread out or diffract.
However, the number of photons remains the same throughout the process. A photon is a fundamental particle of light, and it behaves as a single quantum entity. When a photon interacts with a material or passes through a slit, it can experience diffraction, which affects the distribution of the photon's intensity or probability of detection at different points on a screen or detector.
The diffraction of light through a single slit or multiple slits can create an interference pattern or a pattern of light and dark regions on a screen. This pattern arises due to the superposition of different diffracted waves from various points on the slit(s), resulting in constructive and destructive interference.
So, while the diffraction of light may cause the spreading out of the wavefront, it does not result in the creation of additional photons. The total number of photons remains conserved during diffraction phenomena.