## 2 Experiments  
The experimental setup is shown in Figure 1. The laser beam (351 nm) pumps a 3-mm thin BBO crystal to generate non-degenerate entangled photon pairs through the SPDC process. The wavelengths of the signal photons and idler photons are 633 nm and 788 nm, respectively. The polarizations of signal and idler photons are horizontal and vertical, respectively. Furthermore, they are designed to emit in the same direction of the pump. In other words, the SPDC process generates Type II, collinear and non-degenerate entangled photon pairs. Right after the crystal, there is the object (a single slit or a double slit). For the double slit used in experiments, the width of each slit is 0.15 mm and the distance between the center of each slit is 0.6 mm. For the single slit used in experiments, the width is 0.3 mm. The objects are put as close as possible to the crystal to rule out the possibility that a pair of entangled photons passes through different slits when a double slit is used as the object. There is a convex lens with a 1000-mm focal length right after the object. After the lens, there is a polarized beam splitter (PBS), which is 450 mm away from the lens, to split the entangled photons beam into two. All signal photons (633 nm, horizontal polarized), are transmitted and all idler photons (788 nm, vertical polarized) are reflected. Two single photon detectors \(D_{1}\) and \(D_{2}\) are at an equal distance (1000 mm) away from the objects on the Fourier transformation plane of the lens. The single photon detectors record each photons reaching them, and the output electric pulses from them are input into a coincidence circuit to record coincidence counts (C.C.). Figure 1: Schematic setup of the experiments. When one of the fiber tips is scanned and the other fiber tip is fixed, the ghost interference-diffraction of the object is measured. When both fiber tips are scanned synchronously along the directions of arrows as shown in the figure, the non-degenerate quantum lithography of the interference-diffraction pattern of the object is measured. C.C., coincidence counts. First, we study the diffraction of non-degenerate biphotons. The object is a single slit, the width of which is 0.3 mm. In the first measurement, the detector \(D_{2}\) is fixed, and detector \(D_{1}\) is scanned. The normalized coincidence counting rate distribution is shown in Figure 2a as the function of coordinates of \(D_{1}\) on plane \(X_{1}\). In the second measurement, the detector \(D_{1}\) is fixed, and detector \(D_{2}\) is scanned. The normalized coincidence counting rate distribution is shown in Figure 2b as the function of coordinates of \(D_{2}\) on plane \(X_{2}\). In the third measurement, the detector \(D_{1}\) and \(D_{2}\) are scanned synchronously. With the help of the beam splitter, it is equivalent to recording the distribution of diffracted biphotons using two-photon absorption (TPA) material on the Fourier transformation plane of the lens. The normalized coincidence counting rate distribution is shown in Figure 2c as the function of the coordinates of detectors on their respective planes. In the measurements of Figure 2a,b, the results are the measurements of non-degenerate ghost diffraction [10]. The measurement of Figure 2c is the diffraction of non-degenerate biphotons through the single slit or the non-degenerate quantum lithography of the interference-diffraction pattern of the single slit. The FWHM of the diffraction pattern in Figure 2a,c's measurements are 1.23 mm, 0.99 mm and 0.55 mm, respectively. The ratio between them is 2.26:1.82:1. We notice that the ratio between wavelengths of the idler (788 nm), signal (633 nm) and pump light (351 nm) is 2.25:1.80:1. We know that the classical imaging limit of a regular imaging system is determined by the size of the diffraction pattern of the effective optical aperture of the system. The above experiment shows that the FWHM of the diffraction pattern of the non-degenerate biphotons is narrower than those of signal and idler photons.