[1] F. Jelezko, J. Wrachtrup. Single defect centres in diamond: a review. Phys. Status Solidi A, 2006, 203: 3207-3225.

[2] M. W. Doherty, N. B. Manson, P. Delaney, F. Jelezko, J. Wrachtrup, L. C. Hollenberg. The nitrogen-vacancy colour centre in diamond. Phys. Rep., 2013, 528: 1-45.

[3] R. Schirhagl, K. Chang, M. Loretz, C. L. Degen. Nitrogen-vacancy centers in diamond: nanoscale sensors for physics and biology. Annu. Rev. Phys. Chem, 2014, 65: 83-105.

[4] L. J. Rogers, K. D. Jahnke, M. H. Metsch, A. Sipahigil, J. M. Binder, T. Teraji, H. Sumiya, J. Isoya, M. D. Lukin, P. Hemmer, F. Jelezko. All-optical initialization, readout, and coherent preparation of single silicon-vacancy spins in diamond. Phys. Rev. Lett., 2014, 113: 263602.

[5] A. Gottscholl, M. Kianinia, V. Soltamov, S. Orlinskii, G. Mamin, C. Bradac, C. Kasper, K. Krambrock, A. Sperlich, M. Toth, I. Aharonovich, V. Dyakonov. Initialization and read-out of intrinsic spin defects in a van der Waals crystal at room temperature. Nat. Mater., 2020, 19: 540-545.

[6] J.-W. Fan, I. Cojocaru, J. Becker, I. V. Fedotov, M. H. A. Alkahtani, A. Alajlan, S. Blakley, M. Rezaee, A. Lyamkina, Y. N. Palyanov, Y. M. Borzdov, Y.-P. Yang, A. Zheltikov, P. Hemmer, A. V. Akimov. Germanium-vacancy color center in diamond as a temperature sensor. ACS Photon., 2018, 5: 765-770.

[7] G. Wolfowicz, C. P. Anderson, B. Diler, O. G. Poluektov, F. J. Heremans, D. D. Awschalom. Vanadium spin qubits as telecom quantum emitters in silicon carbide. Sci. Adv., 2020, 6: eaaz1192.

[8] E. Rittweger, K. Y. Han, S. E. Irvine, C. Eggeling, S. W. Hell. STED microscopy reveals crystal colour centers with nanometric resolution. Nat. Photonics, 2009, 3: 144-147.

[9] X.-S. Yang, Y.-K. Tzeng, Z. Zhu, Z.-H. Huang, X.-Z. Chen, Y.-J. Liu, H.-C. Chang, L. Huang, W.-D. Li, P. Xi. Sub-diffraction imaging of nitrogen-vacancy centers in diamond by stimulated emission depletion and structured illumination. RSC Adv., 2014, 4: 11305-11310.

[10] M. Pfender, N. Aslam, G. Waldherr, P. Neumann, J. Wrachtrup. Single-spin stochastic optical reconstruction microscopy. Proc. Natl. Acad. Sci. USA, 2014, 111: 14669-14674.

[11] X.-D. Chen, C.-L. Zou, Z.-J. Gong, C.-H. Dong, G.-C. Guo, F.-W. Sun. Subdiffraction optical manipulation of the charge state of nitrogen vacancy center in diamond. Light Sci. Appl., 2015, 4: e230.

[12] E. Bersin, M. Walsh, S. L. Mouradian, M. E. Trusheim, T. Schröder, D. Englund. Individual control and readout of qubits in a sub-diffraction volume. npj Quantum Inf., 2019, 5: 38.

[13] J.-C. Jaskula, E. Bauch, S. Arroyo-Camejo, M. D. Lukin, S. W. Hell, A. S. Trifonov, R. L. Walsworth. Superresolution optical magnetic imaging and spectroscopy using individual electronic spins in diamond. Opt. Express, 2017, 25: 11048-11064.

[14] M. Barbiero, S. Castelletto, X. Gan, M. Gu. Spin-manipulated nanoscopy for single nitrogen-vacancy center localizations in nanodiamonds. Light Sci. Appl., 2017, 6: e17085.

[15] E. H. Rego, L. Shao, J. J. Macklin, L. Winoto, G. A. Johansson, N. Kamps-Hughes, M. W. Davidson, M. G. L. Gustafsson. Nonlinear structured-illumination microscopy with a photoswitchable protein reveals cellular structures at 50-nm resolution. Proc. Natl. Acad. Sci. USA, 2012, 109: E135-E143.

[16] D. Denkova, M. Plöschner, M. Das, L. M. Parker, X. Zheng, Y. Lu, A. Orth, N. H. Packer, J. A. Piper. 3D sub-diffraction imaging in a conventional confocal configuration by exploiting super-linear emitters. Nat. Commun., 2019, 10: 3695.

[17] G.-Y. Zhao, C. Zheng, C.-F. Kuang, R.-J. Zhou, M. M. Kabir, K. C. Toussaint, W.-S. Wang, L. Xu, H.-F. Li, P. Xiu, X. Liu. Nonlinear focal modulation microscopy. Phys. Rev. lett., 2018, 120: 193901.

[18] R. Heintzmann, T. M. Jovin, C. Cremer. Saturated patterned excitation microscopy—a concept for optical resolution improvement. J. Opt. Soc. Am. A, 2002, 19: 1599-1609.

[19] X.-D. Chen, S. Li, B. Du, Y. Dong, Z.-H. Wang, G.-C. Guo, F.-W. Sun. High-resolution multiphoton microscopy with a low-power continuous wave laser pump. Opt. Lett., 2018, 43: 699-702.

[20] I. Gregor, M. Spiecker, R. Petrovsky, J. Großhans, R. Ros, J. Enderlein. Rapid nonlinear image scanning microscopy. Nat. Methods, 2017, 14: 1087-1089.

[21] K. Fujita, M. Kobayashi, S. Kawano, M. Yamanaka, S. Kawata. High-resolution confocal microscopy by saturated excitation of fluorescence. Phys. Rev. Lett., 2007, 99: 228105.

[22] Y. Nawa, Y. Yonemaru, A. Kasai, R. Oketani, H. Hashimoto, N. I. Smith, K. Fujita. Saturated excitation microscopy using differential excitation for efficient detection of nonlinear fluorescence signals. APL Photon., 2018, 3: 080805.

[23] C. Li, V. N. Le, X. Wang, X. Hao, X. Liu, C. Kuang. Resolution enhancement and background suppression in optical super-resolution imaging for biological applications. Laser Photon. Rev., 2020, 14: 1900084.

[24] J. Vogelsang, T. Cordes, C. Forthmann, C. Steinhauer, P. Tinnefeld. Intrinsically resolution enhancing probes for confocal microscopy. Nano Lett., 2010, 10: 672-679.

[25] S. Hennig, S. van de Linde, M. Heilemann, M. Sauer. Quantum dot triexciton imaging with three-dimensional subdiffraction resolution. Nano Lett., 2009, 9: 2466-2470.

[26] M. Plöschner, D. Denkova, S. D. Camillis, M. Das, L. M. Parker, X. Zheng, Y. Lu, S. Ojosnegros, J. A. Piper. Simultaneous super-linear excitation-emission and emission depletion allows imaging of upconversion nanoparticles with higher sub-diffraction resolution. Opt. Express, 2020, 28: 24308-24326.

[27] S. De Camillis, P. Ren, Y. Cao, M. Plöschner, D. Denkova, X. Zheng, Y. Lu, J. A. Piper. Controlling the non-linear emission of upconversion nanoparticles to enhance super-resolution imaging performance. Nanoscale, 2020, 12: 20347-20355.

[28] C. Chen, F. Wang, S. Wen, Q. P. Su, M. C. L. Wu, Y. Liu, B. Wang, D. Li, X. Shan, M. Kianinia, I. Aharonovich, M. Toth, S. P. Jackson, P. Xi, D. Jin. Multi-photon near-infrared emission saturation nanoscopy using upconversion nanoparticles. Nat. Commun., 2018, 9: 3290.

[29] X.-D. Chen, L.-M. Zhou, C.-L. Zou, C.-C. Li, Y. Dong, F.-W. Sun, G.-C. Guo. Spin depolarization effect induced by charge state conversion of nitrogen vacancy center in diamond. Phys. Rev. B, 2015, 92: 104301.

[30] R. Chapman, T. Plakhotnik. Anomalous saturation effects due to optical spin depolarization in nitrogen-vacancy centers in diamond nanocrystals. Phys. Rev. B, 2012, 86: 045204.

[31] K. Y. Han, D. Wildanger, E. Rittweger, J. Meijer, S. Pezzagna, S. W. Hell, C. Eggeling. Dark state photophysics of nitrogen-vacancy centres in diamond. New J. Phys., 2012, 14: 123002.

[32] X.-D. Chen, S. Li, A. Shen, Y. Dong, C.-H. Dong, G.-C. Guo, F.-W. Sun. Near-infrared-enhanced charge-state conversion for low-power optical nanoscopy with nitrogen-vacancy centers in diamond. Phys. Rev. Appl., 2017, 7: 014008.

[33] N. Aslam, G. Waldherr, P. Neumann, F. Jelezko, J. Wrachtrup. Photo-induced ionization dynamics of the nitrogen vacancy defect in diamond investigated by single-shot charge state detection. New J. Phys., 2013, 15: 013064.

[34] G. Zhao, M. M. Kabir, K. C. Toussaint, C. Kuang, C. Zheng, Z. Yu, X. Liu. Saturated absorption competition microscopy. Optica, 2017, 4: 633-636.

[35] K. Korobchevskaya, C. Peres, Z.-B. Li, A. Antipov, C. J. R. Sheppard, A. Diaspro, P. Bianchini. Intensity weighted subtraction microscopy approach for image contrast and resolution enhancement. Sci. Rep., 2016, 6: 25816.

[36] S. J. Hewlett, T. Wilson. Resolution enhancement in three-dimensional confocal microscopy. Mach. Vis. Appl., 1991, 4: 233-242.

[37] S. Dhomkar, P. R. Zangara, J. Henshaw, C. A. Meriles. On-demand generation of neutral and negatively charged silicon-vacancy centers in diamond. Phys. Rev. Lett., 2018, 120: 117401.

[38] G. Wolfowicz, C. P. Anderson, A. L. Yeats, S. J. Whiteley, J. Niklas, O. G. Poluektov, F. J. Heremans, D. D. Awschalom. Optical charge state control of spin defects in 4H-SIC. Nat. Commun., 2017, 8: 1876.

[39] X. Ouyang, F. Qin, Z. Ji, T. Zhang, J. Xu, Z. Feng, S. Yang, Y. Cao, K. Shi, L. Jiang, X. Li. Invited article: saturation scattering competition for non-fluorescence single-wavelength super-resolution imaging. APL Photon., 2018, 3: 110801.

[40] X.-D. Chen, Y. Zheng, B. Du, D.-F. Li, S. Li, Y. Dong, G.-C. Guo, F.-W. Sun. High-contrast quantum imaging with time-gated fluorescence detection. Phys. Rev. Appl., 2019, 11: 064024.

[41] B.-W. Zhao, X.-D. Chen, E.-H. Wang, Y. Zheng, B. Du, S. Li, Y. Dong, G.-C. Guo, F.-W. Sun. Stimulated emission assisted time-gated detection of a solid-state spin. Appl. Opt., 2020, 59: 6291-6295.

[42] G. Zhao, C. Kuang, Z. Ding, X. Liu. Resolution enhancement of saturated fluorescence emission difference microscopy. Opt. Express, 2016, 24: 23596-23609.