Whether it will be realized in eternity depends on the existence of our entire universe. It depends on the intensity and quality (alignment of the green laser pointer), but it is possible. In fact, one experiment was to irradiate a target on the moon with a laser. Compared with the rest of the light from the earth, even high-quality laser light will spread too much over this distance to be unnoticeable.
Because we can see starlight galaxies billions of light-years away, and these are just photons emitted by laser pointers. Only when photons hit our retina or telescope detectors or other objects, their journey will end. A laser pointer will spread light, but the quantum law is that a photon is an inseparable packet of energy, so if a sensitive detector manages to get a single photon to hit it, the photon will spread out and then be detected. The frog’s eye can detect a single photon.
Like all waves, this wave spreads with distance. So your laser photons are carried by these waves and propagate with these waves. If you ask me, why are the photons of lasers spreading recently compared to other light sources? I can say that all photons have the same frequency, and they are affected by waves at the same rate and vibration. But with the quantum region of distance, they lose their harmony. This view also explains the duality movement of light; waves or particles? This movement is the same as the movement of dust particles above the water waves in the washbasin. You can observe at home 🙂 (The result of one seam and double seam is almost the same)
I will answer this question only in terms of diffraction, because this is the basic limitation of the divergence of the laser beam. Since the width of the beam is limited, diffraction is the spread of the beam. It is the foundation of physics. Even the uncertainty principle is an aspect of the same thing. That is, the more you restrict the position of a particle, the less you know about its direction. To some extent, this all boils down to wave mechanics.
Consider each point in the wave propagating outward in a circular fashion from that point (like the ripples of water falling from a rock into the water). If a point next to this point also propagates outward with the same phase (the peak and trough oscillate together), then the two circular waves will add together to form a complex wave.
As the “emitter” line increases, the wave starts to look like a plane wave, but the edges will still propagate outward. As the “beam” of the wave gets wider from the transmitter, the net effect is that it spreads smaller and smaller. Whether this is a light wave from a laser pointer, a water wave, or a slit in a quantum experiment, the result is the same. Therefore, we can say that the divergence of the laser beam is due to the fundamental physics and the spatial superposition of the coherent emitted photons of the laser.